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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>36.15. Informix Compatibility Mode</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="ecpg-sql-whenever.html" title="WHENEVER" /><link rel="next" href="ecpg-develop.html" title="36.16. Internals" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">36.15. <span xmlns="http://www.w3.org/1999/xhtml" class="productname">Informix</span> Compatibility Mode</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="ecpg-sql-whenever.html" title="WHENEVER">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="ecpg.html" title="Chapter 36. ECPG - Embedded SQL in C">Up</a></td><th width="60%" align="center">Chapter 36. <span xmlns="http://www.w3.org/1999/xhtml" class="application">ECPG</span> - Embedded <acronym xmlns="http://www.w3.org/1999/xhtml" class="acronym">SQL</acronym> in C</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="ecpg-develop.html" title="36.16. Internals">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="ECPG-INFORMIX-COMPAT"><div class="titlepage"><div><div><h2 class="title" style="clear: both">36.15. <span class="productname">Informix</span> Compatibility Mode</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="ecpg-informix-compat.html#ECPG-INFORMIX-TYPES">36.15.1. Additional Types</a></span></dt><dt><span class="sect2"><a href="ecpg-informix-compat.html#ECPG-INFORMIX-STATEMENTS">36.15.2. Additional/Missing Embedded SQL Statements</a></span></dt><dt><span class="sect2"><a href="ecpg-informix-compat.html#ECPG-INFORMIX-SQLDA">36.15.3. Informix-compatible SQLDA Descriptor Areas</a></span></dt><dt><span class="sect2"><a href="ecpg-informix-compat.html#ECPG-INFORMIX-FUNCTIONS">36.15.4. Additional Functions</a></span></dt><dt><span class="sect2"><a href="ecpg-informix-compat.html#ECPG-INFORMIX-CONSTANTS">36.15.5. Additional Constants</a></span></dt></dl></div><p>
<code class="command">ecpg</code> can be run in a so-called <em class="firstterm">Informix compatibility mode</em>. If
this mode is active, it tries to behave as if it were the <span class="productname">Informix</span>
precompiler for <span class="productname">Informix</span> E/SQL. Generally spoken this will allow you to use
the dollar sign instead of the <code class="literal">EXEC SQL</code> primitive to introduce
embedded SQL commands:
</p><pre class="programlisting">
$int j = 3;
$CONNECT TO :dbname;
$CREATE TABLE test(i INT PRIMARY KEY, j INT);
$INSERT INTO test(i, j) VALUES (7, :j);
$COMMIT;
</pre><p>
</p><div class="note"><h3 class="title">Note</h3><p>
There must not be any white space between the <code class="literal">$</code>
and a following preprocessor directive, that is,
<code class="literal">include</code>, <code class="literal">define</code>, <code class="literal">ifdef</code>,
etc. Otherwise, the preprocessor will parse the token as a host
variable.
</p></div><p>
There are two compatibility modes: <code class="literal">INFORMIX</code>, <code class="literal">INFORMIX_SE</code>
</p><p>
When linking programs that use this compatibility mode, remember to link
against <code class="literal">libcompat</code> that is shipped with ECPG.
</p><p>
Besides the previously explained syntactic sugar, the <span class="productname">Informix</span> compatibility
mode ports some functions for input, output and transformation of data as
well as embedded SQL statements known from E/SQL to ECPG.
</p><p>
<span class="productname">Informix</span> compatibility mode is closely connected to the pgtypeslib library
of ECPG. pgtypeslib maps SQL data types to data types within the C host
program and most of the additional functions of the <span class="productname">Informix</span> compatibility
mode allow you to operate on those C host program types. Note however that
the extent of the compatibility is limited. It does not try to copy <span class="productname">Informix</span>
behavior; it allows you to do more or less the same operations and gives
you functions that have the same name and the same basic behavior but it is
no drop-in replacement if you are using <span class="productname">Informix</span> at the moment. Moreover,
some of the data types are different. For example,
<span class="productname">PostgreSQL's</span> datetime and interval types do not
know about ranges like for example <code class="literal">YEAR TO MINUTE</code> so you won't
find support in ECPG for that either.
</p><div class="sect2" id="ECPG-INFORMIX-TYPES"><div class="titlepage"><div><div><h3 class="title">36.15.1. Additional Types</h3></div></div></div><p>
The Informix-special "string" pseudo-type for storing right-trimmed character string data is now
supported in Informix-mode without using <code class="literal">typedef</code>. In fact, in Informix-mode,
ECPG refuses to process source files that contain <code class="literal">typedef sometype string;</code>
</p><pre class="programlisting">
EXEC SQL BEGIN DECLARE SECTION;
string userid; /* this variable will contain trimmed data */
EXEC SQL END DECLARE SECTION;
EXEC SQL FETCH MYCUR INTO :userid;
</pre><p>
</p></div><div class="sect2" id="ECPG-INFORMIX-STATEMENTS"><div class="titlepage"><div><div><h3 class="title">36.15.2. Additional/Missing Embedded SQL Statements</h3></div></div></div><p>
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">CLOSE DATABASE</code></span></dt><dd><p>
This statement closes the current connection. In fact, this is a
synonym for ECPG's <code class="literal">DISCONNECT CURRENT</code>:
</p><pre class="programlisting">
$CLOSE DATABASE; /* close the current connection */
EXEC SQL CLOSE DATABASE;
</pre><p>
</p></dd><dt><span class="term"><code class="literal">FREE cursor_name</code></span></dt><dd><p>
Due to the differences how ECPG works compared to Informix's ESQL/C (i.e. which steps
are purely grammar transformations and which steps rely on the underlying run-time library)
there is no <code class="literal">FREE cursor_name</code> statement in ECPG. This is because in ECPG,
<code class="literal">DECLARE CURSOR</code> doesn't translate to a function call into
the run-time library that uses to the cursor name. This means that there's no run-time
bookkeeping of SQL cursors in the ECPG run-time library, only in the PostgreSQL server.
</p></dd><dt><span class="term"><code class="literal">FREE statement_name</code></span></dt><dd><p>
<code class="literal">FREE statement_name</code> is a synonym for <code class="literal">DEALLOCATE PREPARE statement_name</code>.
</p></dd></dl></div><p>
</p></div><div class="sect2" id="ECPG-INFORMIX-SQLDA"><div class="titlepage"><div><div><h3 class="title">36.15.3. Informix-compatible SQLDA Descriptor Areas</h3></div></div></div><p>
Informix-compatible mode supports a different structure than the one described in
<a class="xref" href="ecpg-descriptors.html#ECPG-SQLDA-DESCRIPTORS" title="36.7.2. SQLDA Descriptor Areas">Section 36.7.2</a>. See below:
</p><pre class="programlisting">
struct sqlvar_compat
{
short sqltype;
int sqllen;
char *sqldata;
short *sqlind;
char *sqlname;
char *sqlformat;
short sqlitype;
short sqlilen;
char *sqlidata;
int sqlxid;
char *sqltypename;
short sqltypelen;
short sqlownerlen;
short sqlsourcetype;
char *sqlownername;
int sqlsourceid;
char *sqlilongdata;
int sqlflags;
void *sqlreserved;
};
struct sqlda_compat
{
short sqld;
struct sqlvar_compat *sqlvar;
char desc_name[19];
short desc_occ;
struct sqlda_compat *desc_next;
void *reserved;
};
typedef struct sqlvar_compat sqlvar_t;
typedef struct sqlda_compat sqlda_t;
</pre><p>
</p><p>
The global properties are:
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">sqld</code></span></dt><dd><p>
The number of fields in the <code class="literal">SQLDA</code> descriptor.
</p></dd><dt><span class="term"><code class="literal">sqlvar</code></span></dt><dd><p>
Pointer to the per-field properties.
</p></dd><dt><span class="term"><code class="literal">desc_name</code></span></dt><dd><p>
Unused, filled with zero-bytes.
</p></dd><dt><span class="term"><code class="literal">desc_occ</code></span></dt><dd><p>
Size of the allocated structure.
</p></dd><dt><span class="term"><code class="literal">desc_next</code></span></dt><dd><p>
Pointer to the next SQLDA structure if the result set contains more than one record.
</p></dd><dt><span class="term"><code class="literal">reserved</code></span></dt><dd><p>
Unused pointer, contains NULL. Kept for Informix-compatibility.
</p></dd></dl></div><p>
The per-field properties are below, they are stored in the <code class="literal">sqlvar</code> array:
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">sqltype</code></span></dt><dd><p>
Type of the field. Constants are in <code class="literal">sqltypes.h</code>
</p></dd><dt><span class="term"><code class="literal">sqllen</code></span></dt><dd><p>
Length of the field data.
</p></dd><dt><span class="term"><code class="literal">sqldata</code></span></dt><dd><p>
Pointer to the field data. The pointer is of <code class="literal">char *</code> type,
the data pointed by it is in a binary format. Example:
</p><pre class="programlisting">
int intval;
switch (sqldata->sqlvar[i].sqltype)
{
case SQLINTEGER:
intval = *(int *)sqldata->sqlvar[i].sqldata;
break;
...
}
</pre><p>
</p></dd><dt><span class="term"><code class="literal">sqlind</code></span></dt><dd><p>
Pointer to the NULL indicator. If returned by DESCRIBE or FETCH then it's always a valid pointer.
If used as input for <code class="literal">EXECUTE ... USING sqlda;</code> then NULL-pointer value means
that the value for this field is non-NULL. Otherwise a valid pointer and <code class="literal">sqlitype</code>
has to be properly set. Example:
</p><pre class="programlisting">
if (*(int2 *)sqldata->sqlvar[i].sqlind != 0)
printf("value is NULL\n");
</pre><p>
</p></dd><dt><span class="term"><code class="literal">sqlname</code></span></dt><dd><p>
Name of the field. 0-terminated string.
</p></dd><dt><span class="term"><code class="literal">sqlformat</code></span></dt><dd><p>
Reserved in Informix, value of <code class="function">PQfformat()</code> for the field.
</p></dd><dt><span class="term"><code class="literal">sqlitype</code></span></dt><dd><p>
Type of the NULL indicator data. It's always SQLSMINT when returning data from the server.
When the <code class="literal">SQLDA</code> is used for a parameterized query, the data is treated
according to the set type.
</p></dd><dt><span class="term"><code class="literal">sqlilen</code></span></dt><dd><p>
Length of the NULL indicator data.
</p></dd><dt><span class="term"><code class="literal">sqlxid</code></span></dt><dd><p>
Extended type of the field, result of <code class="function">PQftype()</code>.
</p></dd><dt><span class="term"><code class="literal">sqltypename</code><br /></span><span class="term"><code class="literal">sqltypelen</code><br /></span><span class="term"><code class="literal">sqlownerlen</code><br /></span><span class="term"><code class="literal">sqlsourcetype</code><br /></span><span class="term"><code class="literal">sqlownername</code><br /></span><span class="term"><code class="literal">sqlsourceid</code><br /></span><span class="term"><code class="literal">sqlflags</code><br /></span><span class="term"><code class="literal">sqlreserved</code></span></dt><dd><p>
Unused.
</p></dd><dt><span class="term"><code class="literal">sqlilongdata</code></span></dt><dd><p>
It equals to <code class="literal">sqldata</code> if <code class="literal">sqllen</code> is larger than 32kB.
</p></dd></dl></div><p>
Example:
</p><pre class="programlisting">
EXEC SQL INCLUDE sqlda.h;
sqlda_t *sqlda; /* This doesn't need to be under embedded DECLARE SECTION */
EXEC SQL BEGIN DECLARE SECTION;
char *prep_stmt = "select * from table1";
int i;
EXEC SQL END DECLARE SECTION;
...
EXEC SQL PREPARE mystmt FROM :prep_stmt;
EXEC SQL DESCRIBE mystmt INTO sqlda;
printf("# of fields: %d\n", sqlda->sqld);
for (i = 0; i < sqlda->sqld; i++)
printf("field %d: \"%s\"\n", sqlda->sqlvar[i]->sqlname);
EXEC SQL DECLARE mycursor CURSOR FOR mystmt;
EXEC SQL OPEN mycursor;
EXEC SQL WHENEVER NOT FOUND GOTO out;
while (1)
{
EXEC SQL FETCH mycursor USING sqlda;
}
EXEC SQL CLOSE mycursor;
free(sqlda); /* The main structure is all to be free(),
* sqlda and sqlda->sqlvar is in one allocated area */
</pre><p>
For more information, see the <code class="literal">sqlda.h</code> header and the
<code class="literal">src/interfaces/ecpg/test/compat_informix/sqlda.pgc</code> regression test.
</p></div><div class="sect2" id="ECPG-INFORMIX-FUNCTIONS"><div class="titlepage"><div><div><h3 class="title">36.15.4. Additional Functions</h3></div></div></div><p>
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="function">decadd</code></span></dt><dd><p>
Add two decimal type values.
</p><pre class="synopsis">
int decadd(decimal *arg1, decimal *arg2, decimal *sum);
</pre><p>
The function receives a pointer to the first operand of type decimal
(<code class="literal">arg1</code>), a pointer to the second operand of type decimal
(<code class="literal">arg2</code>) and a pointer to a value of type decimal that will
contain the sum (<code class="literal">sum</code>). On success, the function returns 0.
<code class="symbol">ECPG_INFORMIX_NUM_OVERFLOW</code> is returned in case of overflow and
<code class="symbol">ECPG_INFORMIX_NUM_UNDERFLOW</code> in case of underflow. -1 is returned for
other failures and <code class="varname">errno</code> is set to the respective <code class="varname">errno</code> number of the
pgtypeslib.
</p></dd><dt><span class="term"><code class="function">deccmp</code></span></dt><dd><p>
Compare two variables of type decimal.
</p><pre class="synopsis">
int deccmp(decimal *arg1, decimal *arg2);
</pre><p>
The function receives a pointer to the first decimal value
(<code class="literal">arg1</code>), a pointer to the second decimal value
(<code class="literal">arg2</code>) and returns an integer value that indicates which is
the bigger value.
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
1, if the value that <code class="literal">arg1</code> points to is bigger than the
value that <code class="literal">var2</code> points to
</p></li><li class="listitem"><p>
-1, if the value that <code class="literal">arg1</code> points to is smaller than the
value that <code class="literal">arg2</code> points to </p></li><li class="listitem"><p>
0, if the value that <code class="literal">arg1</code> points to and the value that
<code class="literal">arg2</code> points to are equal
</p></li></ul></div><p>
</p></dd><dt><span class="term"><code class="function">deccopy</code></span></dt><dd><p>
Copy a decimal value.
</p><pre class="synopsis">
void deccopy(decimal *src, decimal *target);
</pre><p>
The function receives a pointer to the decimal value that should be
copied as the first argument (<code class="literal">src</code>) and a pointer to the
target structure of type decimal (<code class="literal">target</code>) as the second
argument.
</p></dd><dt><span class="term"><code class="function">deccvasc</code></span></dt><dd><p>
Convert a value from its ASCII representation into a decimal type.
</p><pre class="synopsis">
int deccvasc(char *cp, int len, decimal *np);
</pre><p>
The function receives a pointer to string that contains the string
representation of the number to be converted (<code class="literal">cp</code>) as well
as its length <code class="literal">len</code>. <code class="literal">np</code> is a pointer to the
decimal value that saves the result of the operation.
</p><p>
Valid formats are for example:
<code class="literal">-2</code>,
<code class="literal">.794</code>,
<code class="literal">+3.44</code>,
<code class="literal">592.49E07</code> or
<code class="literal">-32.84e-4</code>.
</p><p>
The function returns 0 on success. If overflow or underflow occurred,
<code class="literal">ECPG_INFORMIX_NUM_OVERFLOW</code> or
<code class="literal">ECPG_INFORMIX_NUM_UNDERFLOW</code> is returned. If the ASCII
representation could not be parsed,
<code class="literal">ECPG_INFORMIX_BAD_NUMERIC</code> is returned or
<code class="literal">ECPG_INFORMIX_BAD_EXPONENT</code> if this problem occurred while
parsing the exponent.
</p></dd><dt><span class="term"><code class="function">deccvdbl</code></span></dt><dd><p>
Convert a value of type double to a value of type decimal.
</p><pre class="synopsis">
int deccvdbl(double dbl, decimal *np);
</pre><p>
The function receives the variable of type double that should be
converted as its first argument (<code class="literal">dbl</code>). As the second
argument (<code class="literal">np</code>), the function receives a pointer to the
decimal variable that should hold the result of the operation.
</p><p>
The function returns 0 on success and a negative value if the
conversion failed.
</p></dd><dt><span class="term"><code class="function">deccvint</code></span></dt><dd><p>
Convert a value of type int to a value of type decimal.
</p><pre class="synopsis">
int deccvint(int in, decimal *np);
</pre><p>
The function receives the variable of type int that should be
converted as its first argument (<code class="literal">in</code>). As the second
argument (<code class="literal">np</code>), the function receives a pointer to the
decimal variable that should hold the result of the operation.
</p><p>
The function returns 0 on success and a negative value if the
conversion failed.
</p></dd><dt><span class="term"><code class="function">deccvlong</code></span></dt><dd><p>
Convert a value of type long to a value of type decimal.
</p><pre class="synopsis">
int deccvlong(long lng, decimal *np);
</pre><p>
The function receives the variable of type long that should be
converted as its first argument (<code class="literal">lng</code>). As the second
argument (<code class="literal">np</code>), the function receives a pointer to the
decimal variable that should hold the result of the operation.
</p><p>
The function returns 0 on success and a negative value if the
conversion failed.
</p></dd><dt><span class="term"><code class="function">decdiv</code></span></dt><dd><p>
Divide two variables of type decimal.
</p><pre class="synopsis">
int decdiv(decimal *n1, decimal *n2, decimal *result);
</pre><p>
The function receives pointers to the variables that are the first
(<code class="literal">n1</code>) and the second (<code class="literal">n2</code>) operands and
calculates <code class="literal">n1</code>/<code class="literal">n2</code>. <code class="literal">result</code> is a
pointer to the variable that should hold the result of the operation.
</p><p>
On success, 0 is returned and a negative value if the division fails.
If overflow or underflow occurred, the function returns
<code class="literal">ECPG_INFORMIX_NUM_OVERFLOW</code> or
<code class="literal">ECPG_INFORMIX_NUM_UNDERFLOW</code> respectively. If an attempt to
divide by zero is observed, the function returns
<code class="literal">ECPG_INFORMIX_DIVIDE_ZERO</code>.
</p></dd><dt><span class="term"><code class="function">decmul</code></span></dt><dd><p>
Multiply two decimal values.
</p><pre class="synopsis">
int decmul(decimal *n1, decimal *n2, decimal *result);
</pre><p>
The function receives pointers to the variables that are the first
(<code class="literal">n1</code>) and the second (<code class="literal">n2</code>) operands and
calculates <code class="literal">n1</code>*<code class="literal">n2</code>. <code class="literal">result</code> is a
pointer to the variable that should hold the result of the operation.
</p><p>
On success, 0 is returned and a negative value if the multiplication
fails. If overflow or underflow occurred, the function returns
<code class="literal">ECPG_INFORMIX_NUM_OVERFLOW</code> or
<code class="literal">ECPG_INFORMIX_NUM_UNDERFLOW</code> respectively.
</p></dd><dt><span class="term"><code class="function">decsub</code></span></dt><dd><p>
Subtract one decimal value from another.
</p><pre class="synopsis">
int decsub(decimal *n1, decimal *n2, decimal *result);
</pre><p>
The function receives pointers to the variables that are the first
(<code class="literal">n1</code>) and the second (<code class="literal">n2</code>) operands and
calculates <code class="literal">n1</code>-<code class="literal">n2</code>. <code class="literal">result</code> is a
pointer to the variable that should hold the result of the operation.
</p><p>
On success, 0 is returned and a negative value if the subtraction
fails. If overflow or underflow occurred, the function returns
<code class="literal">ECPG_INFORMIX_NUM_OVERFLOW</code> or
<code class="literal">ECPG_INFORMIX_NUM_UNDERFLOW</code> respectively.
</p></dd><dt><span class="term"><code class="function">dectoasc</code></span></dt><dd><p>
Convert a variable of type decimal to its ASCII representation in a C
char* string.
</p><pre class="synopsis">
int dectoasc(decimal *np, char *cp, int len, int right)
</pre><p>
The function receives a pointer to a variable of type decimal
(<code class="literal">np</code>) that it converts to its textual representation.
<code class="literal">cp</code> is the buffer that should hold the result of the
operation. The parameter <code class="literal">right</code> specifies, how many digits
right of the decimal point should be included in the output. The result
will be rounded to this number of decimal digits. Setting
<code class="literal">right</code> to -1 indicates that all available decimal digits
should be included in the output. If the length of the output buffer,
which is indicated by <code class="literal">len</code> is not sufficient to hold the
textual representation including the trailing zero byte, only a
single <code class="literal">*</code> character is stored in the result and -1 is
returned.
</p><p>
The function returns either -1 if the buffer <code class="literal">cp</code> was too
small or <code class="literal">ECPG_INFORMIX_OUT_OF_MEMORY</code> if memory was
exhausted.
</p></dd><dt><span class="term"><code class="function">dectodbl</code></span></dt><dd><p>
Convert a variable of type decimal to a double.
</p><pre class="synopsis">
int dectodbl(decimal *np, double *dblp);
</pre><p>
The function receives a pointer to the decimal value to convert
(<code class="literal">np</code>) and a pointer to the double variable that
should hold the result of the operation (<code class="literal">dblp</code>).
</p><p>
On success, 0 is returned and a negative value if the conversion
failed.
</p></dd><dt><span class="term"><code class="function">dectoint</code></span></dt><dd><p>
Convert a variable to type decimal to an integer.
</p><pre class="synopsis">
int dectoint(decimal *np, int *ip);
</pre><p>
The function receives a pointer to the decimal value to convert
(<code class="literal">np</code>) and a pointer to the integer variable that
should hold the result of the operation (<code class="literal">ip</code>).
</p><p>
On success, 0 is returned and a negative value if the conversion
failed. If an overflow occurred, <code class="literal">ECPG_INFORMIX_NUM_OVERFLOW</code>
is returned.
</p><p>
Note that the ECPG implementation differs from the <span class="productname">Informix</span>
implementation. <span class="productname">Informix</span> limits an integer to the range from -32767 to
32767, while the limits in the ECPG implementation depend on the
architecture (<code class="literal">-INT_MAX .. INT_MAX</code>).
</p></dd><dt><span class="term"><code class="function">dectolong</code></span></dt><dd><p>
Convert a variable to type decimal to a long integer.
</p><pre class="synopsis">
int dectolong(decimal *np, long *lngp);
</pre><p>
The function receives a pointer to the decimal value to convert
(<code class="literal">np</code>) and a pointer to the long variable that
should hold the result of the operation (<code class="literal">lngp</code>).
</p><p>
On success, 0 is returned and a negative value if the conversion
failed. If an overflow occurred, <code class="literal">ECPG_INFORMIX_NUM_OVERFLOW</code>
is returned.
</p><p>
Note that the ECPG implementation differs from the <span class="productname">Informix</span>
implementation. <span class="productname">Informix</span> limits a long integer to the range from
-2,147,483,647 to 2,147,483,647, while the limits in the ECPG
implementation depend on the architecture (<code class="literal">-LONG_MAX ..
LONG_MAX</code>).
</p></dd><dt><span class="term"><code class="function">rdatestr</code></span></dt><dd><p>
Converts a date to a C char* string.
</p><pre class="synopsis">
int rdatestr(date d, char *str);
</pre><p>
The function receives two arguments, the first one is the date to
convert (<code class="literal">d</code>) and the second one is a pointer to the target
string. The output format is always <code class="literal">yyyy-mm-dd</code>, so you need
to allocate at least 11 bytes (including the zero-byte terminator) for the
string.
</p><p>
The function returns 0 on success and a negative value in case of
error.
</p><p>
Note that ECPG's implementation differs from the <span class="productname">Informix</span>
implementation. In <span class="productname">Informix</span> the format can be influenced by setting
environment variables. In ECPG however, you cannot change the output
format.
</p></dd><dt><span class="term"><code class="function">rstrdate</code></span></dt><dd><p>
Parse the textual representation of a date.
</p><pre class="synopsis">
int rstrdate(char *str, date *d);
</pre><p>
The function receives the textual representation of the date to convert
(<code class="literal">str</code>) and a pointer to a variable of type date
(<code class="literal">d</code>). This function does not allow you to specify a format
mask. It uses the default format mask of <span class="productname">Informix</span> which is
<code class="literal">mm/dd/yyyy</code>. Internally, this function is implemented by
means of <code class="function">rdefmtdate</code>. Therefore, <code class="function">rstrdate</code> is
not faster and if you have the choice you should opt for
<code class="function">rdefmtdate</code> which allows you to specify the format mask
explicitly.
</p><p>
The function returns the same values as <code class="function">rdefmtdate</code>.
</p></dd><dt><span class="term"><code class="function">rtoday</code></span></dt><dd><p>
Get the current date.
</p><pre class="synopsis">
void rtoday(date *d);
</pre><p>
The function receives a pointer to a date variable (<code class="literal">d</code>)
that it sets to the current date.
</p><p>
Internally this function uses the <a class="xref" href="ecpg-pgtypes.html#PGTYPESDATETODAY"><code class="function">PGTYPESdate_today</code></a>
function.
</p></dd><dt><span class="term"><code class="function">rjulmdy</code></span></dt><dd><p>
Extract the values for the day, the month and the year from a variable
of type date.
</p><pre class="synopsis">
int rjulmdy(date d, short mdy[3]);
</pre><p>
The function receives the date <code class="literal">d</code> and a pointer to an array
of 3 short integer values <code class="literal">mdy</code>. The variable name indicates
the sequential order: <code class="literal">mdy[0]</code> will be set to contain the
number of the month, <code class="literal">mdy[1]</code> will be set to the value of the
day and <code class="literal">mdy[2]</code> will contain the year.
</p><p>
The function always returns 0 at the moment.
</p><p>
Internally the function uses the <a class="xref" href="ecpg-pgtypes.html#PGTYPESDATEJULMDY"><code class="function">PGTYPESdate_julmdy</code></a>
function.
</p></dd><dt><span class="term"><code class="function">rdefmtdate</code></span></dt><dd><p>
Use a format mask to convert a character string to a value of type
date.
</p><pre class="synopsis">
int rdefmtdate(date *d, char *fmt, char *str);
</pre><p>
The function receives a pointer to the date value that should hold the
result of the operation (<code class="literal">d</code>), the format mask to use for
parsing the date (<code class="literal">fmt</code>) and the C char* string containing
the textual representation of the date (<code class="literal">str</code>). The textual
representation is expected to match the format mask. However you do not
need to have a 1:1 mapping of the string to the format mask. The
function only analyzes the sequential order and looks for the literals
<code class="literal">yy</code> or <code class="literal">yyyy</code> that indicate the
position of the year, <code class="literal">mm</code> to indicate the position of
the month and <code class="literal">dd</code> to indicate the position of the
day.
</p><p>
The function returns the following values:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
0 - The function terminated successfully.
</p></li><li class="listitem"><p>
<code class="literal">ECPG_INFORMIX_ENOSHORTDATE</code> - The date does not contain
delimiters between day, month and year. In this case the input
string must be exactly 6 or 8 bytes long but isn't.
</p></li><li class="listitem"><p>
<code class="literal">ECPG_INFORMIX_ENOTDMY</code> - The format string did not
correctly indicate the sequential order of year, month and day.
</p></li><li class="listitem"><p>
<code class="literal">ECPG_INFORMIX_BAD_DAY</code> - The input string does not
contain a valid day.
</p></li><li class="listitem"><p>
<code class="literal">ECPG_INFORMIX_BAD_MONTH</code> - The input string does not
contain a valid month.
</p></li><li class="listitem"><p>
<code class="literal">ECPG_INFORMIX_BAD_YEAR</code> - The input string does not
contain a valid year.
</p></li></ul></div><p>
</p><p>
Internally this function is implemented to use the <a class="xref" href="ecpg-pgtypes.html#PGTYPESDATEDEFMTASC"><code class="function">PGTYPESdate_defmt_asc</code></a> function. See the reference there for a
table of example input.
</p></dd><dt><span class="term"><code class="function">rfmtdate</code></span></dt><dd><p>
Convert a variable of type date to its textual representation using a
format mask.
</p><pre class="synopsis">
int rfmtdate(date d, char *fmt, char *str);
</pre><p>
The function receives the date to convert (<code class="literal">d</code>), the format
mask (<code class="literal">fmt</code>) and the string that will hold the textual
representation of the date (<code class="literal">str</code>).
</p><p>
On success, 0 is returned and a negative value if an error occurred.
</p><p>
Internally this function uses the <a class="xref" href="ecpg-pgtypes.html#PGTYPESDATEFMTASC"><code class="function">PGTYPESdate_fmt_asc</code></a>
function, see the reference there for examples.
</p></dd><dt><span class="term"><code class="function">rmdyjul</code></span></dt><dd><p>
Create a date value from an array of 3 short integers that specify the
day, the month and the year of the date.
</p><pre class="synopsis">
int rmdyjul(short mdy[3], date *d);
</pre><p>
The function receives the array of the 3 short integers
(<code class="literal">mdy</code>) and a pointer to a variable of type date that should
hold the result of the operation.
</p><p>
Currently the function returns always 0.
</p><p>
Internally the function is implemented to use the function <a class="xref" href="ecpg-pgtypes.html#PGTYPESDATEMDYJUL"><code class="function">PGTYPESdate_mdyjul</code></a>.
</p></dd><dt><span class="term"><code class="function">rdayofweek</code></span></dt><dd><p>
Return a number representing the day of the week for a date value.
</p><pre class="synopsis">
int rdayofweek(date d);
</pre><p>
The function receives the date variable <code class="literal">d</code> as its only
argument and returns an integer that indicates the day of the week for
this date.
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
0 - Sunday
</p></li><li class="listitem"><p>
1 - Monday
</p></li><li class="listitem"><p>
2 - Tuesday
</p></li><li class="listitem"><p>
3 - Wednesday
</p></li><li class="listitem"><p>
4 - Thursday
</p></li><li class="listitem"><p>
5 - Friday
</p></li><li class="listitem"><p>
6 - Saturday
</p></li></ul></div><p>
</p><p>
Internally the function is implemented to use the function <a class="xref" href="ecpg-pgtypes.html#PGTYPESDATEDAYOFWEEK"><code class="function">PGTYPESdate_dayofweek</code></a>.
</p></dd><dt><span class="term"><code class="function">dtcurrent</code></span></dt><dd><p>
Retrieve the current timestamp.
</p><pre class="synopsis">
void dtcurrent(timestamp *ts);
</pre><p>
The function retrieves the current timestamp and saves it into the
timestamp variable that <code class="literal">ts</code> points to.
</p></dd><dt><span class="term"><code class="function">dtcvasc</code></span></dt><dd><p>
Parses a timestamp from its textual representation
into a timestamp variable.
</p><pre class="synopsis">
int dtcvasc(char *str, timestamp *ts);
</pre><p>
The function receives the string to parse (<code class="literal">str</code>) and a
pointer to the timestamp variable that should hold the result of the
operation (<code class="literal">ts</code>).
</p><p>
The function returns 0 on success and a negative value in case of
error.
</p><p>
Internally this function uses the <a class="xref" href="ecpg-pgtypes.html#PGTYPESTIMESTAMPFROMASC"><code class="function">PGTYPEStimestamp_from_asc</code></a> function. See the reference there
for a table with example inputs.
</p></dd><dt><span class="term"><code class="function">dtcvfmtasc</code></span></dt><dd><p>
Parses a timestamp from its textual representation
using a format mask into a timestamp variable.
</p><pre class="synopsis">
dtcvfmtasc(char *inbuf, char *fmtstr, timestamp *dtvalue)
</pre><p>
The function receives the string to parse (<code class="literal">inbuf</code>), the
format mask to use (<code class="literal">fmtstr</code>) and a pointer to the timestamp
variable that should hold the result of the operation
(<code class="literal">dtvalue</code>).
</p><p>
This function is implemented by means of the <a class="xref" href="ecpg-pgtypes.html#PGTYPESTIMESTAMPDEFMTASC"><code class="function">PGTYPEStimestamp_defmt_asc</code></a> function. See the documentation
there for a list of format specifiers that can be used.
</p><p>
The function returns 0 on success and a negative value in case of
error.
</p></dd><dt><span class="term"><code class="function">dtsub</code></span></dt><dd><p>
Subtract one timestamp from another and return a variable of type
interval.
</p><pre class="synopsis">
int dtsub(timestamp *ts1, timestamp *ts2, interval *iv);
</pre><p>
The function will subtract the timestamp variable that <code class="literal">ts2</code>
points to from the timestamp variable that <code class="literal">ts1</code> points to
and will store the result in the interval variable that <code class="literal">iv</code>
points to.
</p><p>
Upon success, the function returns 0 and a negative value if an
error occurred.
</p></dd><dt><span class="term"><code class="function">dttoasc</code></span></dt><dd><p>
Convert a timestamp variable to a C char* string.
</p><pre class="synopsis">
int dttoasc(timestamp *ts, char *output);
</pre><p>
The function receives a pointer to the timestamp variable to convert
(<code class="literal">ts</code>) and the string that should hold the result of the
operation (<code class="literal">output</code>). It converts <code class="literal">ts</code> to its
textual representation according to the SQL standard, which is
be <code class="literal">YYYY-MM-DD HH:MM:SS</code>.
</p><p>
Upon success, the function returns 0 and a negative value if an
error occurred.
</p></dd><dt><span class="term"><code class="function">dttofmtasc</code></span></dt><dd><p>
Convert a timestamp variable to a C char* using a format mask.
</p><pre class="synopsis">
int dttofmtasc(timestamp *ts, char *output, int str_len, char *fmtstr);
</pre><p>
The function receives a pointer to the timestamp to convert as its
first argument (<code class="literal">ts</code>), a pointer to the output buffer
(<code class="literal">output</code>), the maximal length that has been allocated for
the output buffer (<code class="literal">str_len</code>) and the format mask to
use for the conversion (<code class="literal">fmtstr</code>).
</p><p>
Upon success, the function returns 0 and a negative value if an
error occurred.
</p><p>
Internally, this function uses the <a class="xref" href="ecpg-pgtypes.html#PGTYPESTIMESTAMPFMTASC"><code class="function">PGTYPEStimestamp_fmt_asc</code></a> function. See the reference there for
information on what format mask specifiers can be used.
</p></dd><dt><span class="term"><code class="function">intoasc</code></span></dt><dd><p>
Convert an interval variable to a C char* string.
</p><pre class="synopsis">
int intoasc(interval *i, char *str);
</pre><p>
The function receives a pointer to the interval variable to convert
(<code class="literal">i</code>) and the string that should hold the result of the
operation (<code class="literal">str</code>). It converts <code class="literal">i</code> to its
textual representation according to the SQL standard, which is
be <code class="literal">YYYY-MM-DD HH:MM:SS</code>.
</p><p>
Upon success, the function returns 0 and a negative value if an
error occurred.
</p></dd><dt><span class="term"><code class="function">rfmtlong</code></span></dt><dd><p>
Convert a long integer value to its textual representation using a
format mask.
</p><pre class="synopsis">
int rfmtlong(long lng_val, char *fmt, char *outbuf);
</pre><p>
The function receives the long value <code class="literal">lng_val</code>, the format
mask <code class="literal">fmt</code> and a pointer to the output buffer
<code class="literal">outbuf</code>. It converts the long value according to the format
mask to its textual representation.
</p><p>
The format mask can be composed of the following format specifying
characters:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
<code class="literal">*</code> (asterisk) - if this position would be blank
otherwise, fill it with an asterisk.
</p></li><li class="listitem"><p>
<code class="literal">&</code> (ampersand) - if this position would be
blank otherwise, fill it with a zero.
</p></li><li class="listitem"><p>
<code class="literal">#</code> - turn leading zeroes into blanks.
</p></li><li class="listitem"><p>
<code class="literal"><</code> - left-justify the number in the string.
</p></li><li class="listitem"><p>
<code class="literal">,</code> (comma) - group numbers of four or more digits
into groups of three digits separated by a comma.
</p></li><li class="listitem"><p>
<code class="literal">.</code> (period) - this character separates the
whole-number part of the number from the fractional part.
</p></li><li class="listitem"><p>
<code class="literal">-</code> (minus) - the minus sign appears if the number
is a negative value.
</p></li><li class="listitem"><p>
<code class="literal">+</code> (plus) - the plus sign appears if the number is
a positive value.
</p></li><li class="listitem"><p>
<code class="literal">(</code> - this replaces the minus sign in front of the
negative number. The minus sign will not appear.
</p></li><li class="listitem"><p>
<code class="literal">)</code> - this character replaces the minus and is
printed behind the negative value.
</p></li><li class="listitem"><p>
<code class="literal">$</code> - the currency symbol.
</p></li></ul></div><p>
</p></dd><dt><span class="term"><code class="function">rupshift</code></span></dt><dd><p>
Convert a string to upper case.
</p><pre class="synopsis">
void rupshift(char *str);
</pre><p>
The function receives a pointer to the string and transforms every
lower case character to upper case.
</p></dd><dt><span class="term"><code class="function">byleng</code></span></dt><dd><p>
Return the number of characters in a string without counting trailing
blanks.
</p><pre class="synopsis">
int byleng(char *str, int len);
</pre><p>
The function expects a fixed-length string as its first argument
(<code class="literal">str</code>) and its length as its second argument
(<code class="literal">len</code>). It returns the number of significant characters,
that is the length of the string without trailing blanks.
</p></dd><dt><span class="term"><code class="function">ldchar</code></span></dt><dd><p>
Copy a fixed-length string into a null-terminated string.
</p><pre class="synopsis">
void ldchar(char *src, int len, char *dest);
</pre><p>
The function receives the fixed-length string to copy
(<code class="literal">src</code>), its length (<code class="literal">len</code>) and a pointer to the
destination memory (<code class="literal">dest</code>). Note that you need to reserve at
least <code class="literal">len+1</code> bytes for the string that <code class="literal">dest</code>
points to. The function copies at most <code class="literal">len</code> bytes to the new
location (less if the source string has trailing blanks) and adds the
null-terminator.
</p></dd><dt><span class="term"><code class="function">rgetmsg</code></span></dt><dd><p>
</p><pre class="synopsis">
int rgetmsg(int msgnum, char *s, int maxsize);
</pre><p>
This function exists but is not implemented at the moment!
</p></dd><dt><span class="term"><code class="function">rtypalign</code></span></dt><dd><p>
</p><pre class="synopsis">
int rtypalign(int offset, int type);
</pre><p>
This function exists but is not implemented at the moment!
</p></dd><dt><span class="term"><code class="function">rtypmsize</code></span></dt><dd><p>
</p><pre class="synopsis">
int rtypmsize(int type, int len);
</pre><p>
This function exists but is not implemented at the moment!
</p></dd><dt><span class="term"><code class="function">rtypwidth</code></span></dt><dd><p>
</p><pre class="synopsis">
int rtypwidth(int sqltype, int sqllen);
</pre><p>
This function exists but is not implemented at the moment!
</p></dd><dt id="RSETNULL"><span class="term"><code class="function">rsetnull</code></span></dt><dd><p>
Set a variable to NULL.
</p><pre class="synopsis">
int rsetnull(int t, char *ptr);
</pre><p>
The function receives an integer that indicates the type of the
variable and a pointer to the variable itself that is cast to a C
char* pointer.
</p><p>
The following types exist:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
<code class="literal">CCHARTYPE</code> - For a variable of type <code class="type">char</code> or <code class="type">char*</code>
</p></li><li class="listitem"><p>
<code class="literal">CSHORTTYPE</code> - For a variable of type <code class="type">short int</code>
</p></li><li class="listitem"><p>
<code class="literal">CINTTYPE</code> - For a variable of type <code class="type">int</code>
</p></li><li class="listitem"><p>
<code class="literal">CBOOLTYPE</code> - For a variable of type <code class="type">boolean</code>
</p></li><li class="listitem"><p>
<code class="literal">CFLOATTYPE</code> - For a variable of type <code class="type">float</code>
</p></li><li class="listitem"><p>
<code class="literal">CLONGTYPE</code> - For a variable of type <code class="type">long</code>
</p></li><li class="listitem"><p>
<code class="literal">CDOUBLETYPE</code> - For a variable of type <code class="type">double</code>
</p></li><li class="listitem"><p>
<code class="literal">CDECIMALTYPE</code> - For a variable of type <code class="type">decimal</code>
</p></li><li class="listitem"><p>
<code class="literal">CDATETYPE</code> - For a variable of type <code class="type">date</code>
</p></li><li class="listitem"><p>
<code class="literal">CDTIMETYPE</code> - For a variable of type <code class="type">timestamp</code>
</p></li></ul></div><p>
</p><p>
Here is an example of a call to this function:
</p><pre class="programlisting">
$char c[] = "abc ";
$short s = 17;
$int i = -74874;
rsetnull(CCHARTYPE, (char *) c);
rsetnull(CSHORTTYPE, (char *) &s);
rsetnull(CINTTYPE, (char *) &i);
</pre><p>
</p></dd><dt><span class="term"><code class="function">risnull</code></span></dt><dd><p>
Test if a variable is NULL.
</p><pre class="synopsis">
int risnull(int t, char *ptr);
</pre><p>
The function receives the type of the variable to test (<code class="literal">t</code>)
as well a pointer to this variable (<code class="literal">ptr</code>). Note that the
latter needs to be cast to a char*. See the function <a class="xref" href="ecpg-informix-compat.html#RSETNULL"><code class="function">rsetnull</code></a> for a list of possible variable types.
</p><p>
Here is an example of how to use this function:
</p><pre class="programlisting">
$char c[] = "abc ";
$short s = 17;
$int i = -74874;
risnull(CCHARTYPE, (char *) c);
risnull(CSHORTTYPE, (char *) &s);
risnull(CINTTYPE, (char *) &i);
</pre><p>
</p></dd></dl></div><p>
</p></div><div class="sect2" id="ECPG-INFORMIX-CONSTANTS"><div class="titlepage"><div><div><h3 class="title">36.15.5. Additional Constants</h3></div></div></div><p>
Note that all constants here describe errors and all of them are defined
to represent negative values. In the descriptions of the different
constants you can also find the value that the constants represent in the
current implementation. However you should not rely on this number. You can
however rely on the fact all of them are defined to represent negative
values.
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">ECPG_INFORMIX_NUM_OVERFLOW</code></span></dt><dd><p>
Functions return this value if an overflow occurred in a
calculation. Internally it is defined as -1200 (the <span class="productname">Informix</span>
definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_NUM_UNDERFLOW</code></span></dt><dd><p>
Functions return this value if an underflow occurred in a calculation.
Internally it is defined as -1201 (the <span class="productname">Informix</span> definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_DIVIDE_ZERO</code></span></dt><dd><p>
Functions return this value if an attempt to divide by zero is
observed. Internally it is defined as -1202 (the <span class="productname">Informix</span> definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_BAD_YEAR</code></span></dt><dd><p>
Functions return this value if a bad value for a year was found while
parsing a date. Internally it is defined as -1204 (the <span class="productname">Informix</span>
definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_BAD_MONTH</code></span></dt><dd><p>
Functions return this value if a bad value for a month was found while
parsing a date. Internally it is defined as -1205 (the <span class="productname">Informix</span>
definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_BAD_DAY</code></span></dt><dd><p>
Functions return this value if a bad value for a day was found while
parsing a date. Internally it is defined as -1206 (the <span class="productname">Informix</span>
definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_ENOSHORTDATE</code></span></dt><dd><p>
Functions return this value if a parsing routine needs a short date
representation but did not get the date string in the right length.
Internally it is defined as -1209 (the <span class="productname">Informix</span> definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_DATE_CONVERT</code></span></dt><dd><p>
Functions return this value if an error occurred during date
formatting. Internally it is defined as -1210 (the
<span class="productname">Informix</span> definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_OUT_OF_MEMORY</code></span></dt><dd><p>
Functions return this value if memory was exhausted during
their operation. Internally it is defined as -1211 (the
<span class="productname">Informix</span> definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_ENOTDMY</code></span></dt><dd><p>
Functions return this value if a parsing routine was supposed to get a
format mask (like <code class="literal">mmddyy</code>) but not all fields were listed
correctly. Internally it is defined as -1212 (the <span class="productname">Informix</span> definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_BAD_NUMERIC</code></span></dt><dd><p>
Functions return this value either if a parsing routine cannot parse
the textual representation for a numeric value because it contains
errors or if a routine cannot complete a calculation involving numeric
variables because at least one of the numeric variables is invalid.
Internally it is defined as -1213 (the <span class="productname">Informix</span> definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_BAD_EXPONENT</code></span></dt><dd><p>
Functions return this value if a parsing routine cannot parse
an exponent. Internally it is defined as -1216 (the
<span class="productname">Informix</span> definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_BAD_DATE</code></span></dt><dd><p>
Functions return this value if a parsing routine cannot parse
a date. Internally it is defined as -1218 (the
<span class="productname">Informix</span> definition).
</p></dd><dt><span class="term"><code class="literal">ECPG_INFORMIX_EXTRA_CHARS</code></span></dt><dd><p>
Functions return this value if a parsing routine is passed extra
characters it cannot parse. Internally it is defined as -1264 (the
<span class="productname">Informix</span> definition).
</p></dd></dl></div><p>
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