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>PostgreSQL 8.4.12 Documentation</TH
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>Chapter 32. <SPAN
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>ECPG</SPAN
> - Embedded <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
> in C</TD
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><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="ECPG-PGTYPES"
>32.8. pgtypes library</A
></H1
><P
> The pgtypes library maps <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> database
types to C equivalents that can be used in C programs. It also offers
functions to do basic calculations with those types within C, i.e., without
the help of the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> server. See the
following example:
</P><PRE
CLASS="PROGRAMLISTING"
>EXEC SQL BEGIN DECLARE SECTION;
date date1;
timestamp ts1, tsout;
interval iv1;
char *out;
EXEC SQL END DECLARE SECTION;
PGTYPESdate_today(&date1);
EXEC SQL SELECT started, duration INTO :ts1, :iv1 FROM datetbl WHERE d=:date1;
PGTYPEStimestamp_add_interval(&ts1, &iv1, &tsout);
out = PGTYPEStimestamp_to_asc(&tsout);
printf("Started + duration: %s\n", out);
free(out);</PRE
><P>
</P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN36840"
>32.8.1. The numeric type</A
></H2
><P
> The numeric type offers to do calculations with arbitrary precision. See
<A
HREF="datatype-numeric.html"
>Section 8.1</A
> for the equivalent type in the
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> server. Because of the arbitrary precision this
variable needs to be able to expand and shrink dynamically. That's why you
can only create variables on the heap by means of the
<CODE
CLASS="FUNCTION"
>PGTYPESnumeric_new</CODE
> and <CODE
CLASS="FUNCTION"
>PGTYPESnumeric_free</CODE
>
functions. The decimal type, which is similar but limited in the precision,
can be created on the stack as well as on the heap.
</P
><P
> The following functions can be used to work with the numeric type:
<P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_new</CODE
></DT
><DD
><P
> Request a pointer to a newly allocated numeric variable.
</P><PRE
CLASS="SYNOPSIS"
>numeric *PGTYPESnumeric_new(void);</PRE
><P>
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_free</CODE
></DT
><DD
><P
> Free a numeric type, release all of its memory.
</P><PRE
CLASS="SYNOPSIS"
>void PGTYPESnumeric_free(numeric *var);</PRE
><P>
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_from_asc</CODE
></DT
><DD
><P
> Parse a numeric type from its string notation.
</P><PRE
CLASS="SYNOPSIS"
>numeric *PGTYPESnumeric_from_asc(char *str, char **endptr);</PRE
><P>
Valid formats are for example:
<TT
CLASS="LITERAL"
>-2</TT
>,
<TT
CLASS="LITERAL"
>.794</TT
>,
<TT
CLASS="LITERAL"
>+3.44</TT
>,
<TT
CLASS="LITERAL"
>592.49E07</TT
> or
<TT
CLASS="LITERAL"
>-32.84e-4</TT
>.
If the value could be parsed successfully, a valid pointer is returned,
else the NULL pointer. At the moment ecpg always parses the complete
string and so it currently does not support to store the address of the
first invalid character in <TT
CLASS="LITERAL"
>*endptr</TT
>. You can safely
set <TT
CLASS="LITERAL"
>endptr</TT
> to NULL.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_to_asc</CODE
></DT
><DD
><P
> Returns a pointer to a string allocated by <CODE
CLASS="FUNCTION"
>malloc</CODE
> that contains the string
representation of the numeric type <TT
CLASS="LITERAL"
>num</TT
>.
</P><PRE
CLASS="SYNOPSIS"
>char *PGTYPESnumeric_to_asc(numeric *num, int dscale);</PRE
><P>
The numeric value will be printed with <TT
CLASS="LITERAL"
>dscale</TT
> decimal
digits, with rounding applied if necessary.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_add</CODE
></DT
><DD
><P
> Add two numeric variables into a third one.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_add(numeric *var1, numeric *var2, numeric *result);</PRE
><P>
The function adds the variables <TT
CLASS="LITERAL"
>var1</TT
> and
<TT
CLASS="LITERAL"
>var2</TT
> into the result variable
<TT
CLASS="LITERAL"
>result</TT
>.
The function returns 0 on success and -1 in case of error.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_sub</CODE
></DT
><DD
><P
> Subtract two numeric variables and return the result in a third one.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_sub(numeric *var1, numeric *var2, numeric *result);</PRE
><P>
The function subtracts the variable <TT
CLASS="LITERAL"
>var2</TT
> from
the variable <TT
CLASS="LITERAL"
>var1</TT
>. The result of the operation is
stored in the variable <TT
CLASS="LITERAL"
>result</TT
>.
The function returns 0 on success and -1 in case of error.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_mul</CODE
></DT
><DD
><P
> Multiply two numeric variables and return the result in a third one.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_mul(numeric *var1, numeric *var2, numeric *result);</PRE
><P>
The function multiplies the variables <TT
CLASS="LITERAL"
>var1</TT
> and
<TT
CLASS="LITERAL"
>var2</TT
>. The result of the operation is stored in the
variable <TT
CLASS="LITERAL"
>result</TT
>.
The function returns 0 on success and -1 in case of error.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_div</CODE
></DT
><DD
><P
> Divide two numeric variables and return the result in a third one.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_div(numeric *var1, numeric *var2, numeric *result);</PRE
><P>
The function divides the variables <TT
CLASS="LITERAL"
>var1</TT
> by
<TT
CLASS="LITERAL"
>var2</TT
>. The result of the operation is stored in the
variable <TT
CLASS="LITERAL"
>result</TT
>.
The function returns 0 on success and -1 in case of error.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_cmp</CODE
></DT
><DD
><P
> Compare two numeric variables.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_cmp(numeric *var1, numeric *var2)</PRE
><P>
This function compares two numeric variables. In case of error,
<TT
CLASS="LITERAL"
>INT_MAX</TT
> is returned. On success, the function
returns one of three possible results:
<P
></P
></P><UL
><LI
><P
> 1, if <TT
CLASS="LITERAL"
>var1</TT
> is bigger than <TT
CLASS="LITERAL"
>var2</TT
>
</P
></LI
><LI
><P
> -1, if <TT
CLASS="LITERAL"
>var1</TT
> is smaller than <TT
CLASS="LITERAL"
>var2</TT
>
</P
></LI
><LI
><P
> 0, if <TT
CLASS="LITERAL"
>var1</TT
> and <TT
CLASS="LITERAL"
>var2</TT
> are equal
</P
></LI
></UL
><P>
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_from_int</CODE
></DT
><DD
><P
> Convert an int variable to a numeric variable.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_from_int(signed int int_val, numeric *var);</PRE
><P>
This function accepts a variable of type signed int and stores it
in the numeric variable <TT
CLASS="LITERAL"
>var</TT
>. Upon success, 0 is returned and
-1 in case of a failure.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_from_long</CODE
></DT
><DD
><P
> Convert a long int variable to a numeric variable.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_from_long(signed long int long_val, numeric *var);</PRE
><P>
This function accepts a variable of type signed long int and stores it
in the numeric variable <TT
CLASS="LITERAL"
>var</TT
>. Upon success, 0 is returned and
-1 in case of a failure.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_copy</CODE
></DT
><DD
><P
> Copy over one numeric variable into another one.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_copy(numeric *src, numeric *dst);</PRE
><P>
This function copies over the value of the variable that
<TT
CLASS="LITERAL"
>src</TT
> points to into the variable that <TT
CLASS="LITERAL"
>dst</TT
>
points to. It returns 0 on success and -1 if an error occurs.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_from_double</CODE
></DT
><DD
><P
> Convert a variable of type double to a numeric.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_from_double(double d, numeric *dst);</PRE
><P>
This function accepts a variable of type double and stores the result
in the variable that <TT
CLASS="LITERAL"
>dst</TT
> points to. It returns 0 on success
and -1 if an error occurs.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_to_double</CODE
></DT
><DD
><P
> Convert a variable of type numeric to double.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_to_double(numeric *nv, double *dp)</PRE
><P>
The function converts the numeric value from the variable that
<TT
CLASS="LITERAL"
>nv</TT
> points to into the double variable that <TT
CLASS="LITERAL"
>dp</TT
> points
to. It returns 0 on success and -1 if an error occurs, including
overflow. On overflow, the global variable <TT
CLASS="LITERAL"
>errno</TT
> will be set
to <TT
CLASS="LITERAL"
>PGTYPES_NUM_OVERFLOW</TT
> additionally.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_to_int</CODE
></DT
><DD
><P
> Convert a variable of type numeric to int.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_to_int(numeric *nv, int *ip);</PRE
><P>
The function converts the numeric value from the variable that
<TT
CLASS="LITERAL"
>nv</TT
> points to into the integer variable that <TT
CLASS="LITERAL"
>ip</TT
>
points to. It returns 0 on success and -1 if an error occurs, including
overflow. On overflow, the global variable <TT
CLASS="LITERAL"
>errno</TT
> will be set
to <TT
CLASS="LITERAL"
>PGTYPES_NUM_OVERFLOW</TT
> additionally.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_to_long</CODE
></DT
><DD
><P
> Convert a variable of type numeric to long.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_to_long(numeric *nv, long *lp);</PRE
><P>
The function converts the numeric value from the variable that
<TT
CLASS="LITERAL"
>nv</TT
> points to into the long integer variable that
<TT
CLASS="LITERAL"
>lp</TT
> points to. It returns 0 on success and -1 if an error
occurs, including overflow. On overflow, the global variable
<TT
CLASS="LITERAL"
>errno</TT
> will be set to <TT
CLASS="LITERAL"
>PGTYPES_NUM_OVERFLOW</TT
>
additionally.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_to_decimal</CODE
></DT
><DD
><P
> Convert a variable of type numeric to decimal.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_to_decimal(numeric *src, decimal *dst);</PRE
><P>
The function converts the numeric value from the variable that
<TT
CLASS="LITERAL"
>src</TT
> points to into the decimal variable that
<TT
CLASS="LITERAL"
>dst</TT
> points to. It returns 0 on success and -1 if an error
occurs, including overflow. On overflow, the global variable
<TT
CLASS="LITERAL"
>errno</TT
> will be set to <TT
CLASS="LITERAL"
>PGTYPES_NUM_OVERFLOW</TT
>
additionally.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESnumeric_from_decimal</CODE
></DT
><DD
><P
> Convert a variable of type decimal to numeric.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESnumeric_from_decimal(decimal *src, numeric *dst);</PRE
><P>
The function converts the decimal value from the variable that
<TT
CLASS="LITERAL"
>src</TT
> points to into the numeric variable that
<TT
CLASS="LITERAL"
>dst</TT
> points to. It returns 0 on success and -1 if an error
occurs. Since the decimal type is implemented as a limited version of
the numeric type, overflow cannot occur with this conversion.
</P
></DD
></DL
></DIV
><P>
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN37016"
>32.8.2. The date type</A
></H2
><P
> The date type in C enables your programs to deal with data of the SQL type
date. See <A
HREF="datatype-datetime.html"
>Section 8.5</A
> for the equivalent type in the
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> server.
</P
><P
> The following functions can be used to work with the date type:
<P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
NAME="PGTYPESDATEFROMTIMESTAMP"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESdate_from_timestamp</CODE
></DT
><DD
><P
> Extract the date part from a timestamp.
</P><PRE
CLASS="SYNOPSIS"
>date PGTYPESdate_from_timestamp(timestamp dt);</PRE
><P>
The function receives a timestamp as its only argument and returns the
extracted date part from this timestamp.
</P
></DD
><DT
><A
NAME="PGTYPESDATEFROMASC"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESdate_from_asc</CODE
></DT
><DD
><P
> Parse a date from its textual representation.
</P><PRE
CLASS="SYNOPSIS"
>date PGTYPESdate_from_asc(char *str, char **endptr);</PRE
><P>
The function receives a C char* string <TT
CLASS="LITERAL"
>str</TT
> and a pointer to
a C char* string <TT
CLASS="LITERAL"
>endptr</TT
>. At the moment ecpg always parses
the complete string and so it currently does not support to store the
address of the first invalid character in <TT
CLASS="LITERAL"
>*endptr</TT
>.
You can safely set <TT
CLASS="LITERAL"
>endptr</TT
> to NULL.
</P
><P
> Note that the function always assumes MDY-formatted dates and there is
currently no variable to change that within ecpg.
</P
><P
> <A
HREF="ecpg-pgtypes.html#ECPG-PGTYPESDATE-FROM-ASC-TABLE"
>Table 32-1</A
> shows the allowed input formats.
</P
><DIV
CLASS="TABLE"
><A
NAME="ECPG-PGTYPESDATE-FROM-ASC-TABLE"
></A
><P
><B
>Table 32-1. Valid input formats for <CODE
CLASS="FUNCTION"
>PGTYPESdate_from_asc</CODE
></B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><THEAD
><TR
><TH
>Input</TH
><TH
>Result</TH
></TR
></THEAD
><TBODY
><TR
><TD
><TT
CLASS="LITERAL"
>January 8, 1999</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>1999-01-08</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>1/8/1999</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>1/18/1999</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 18, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>01/02/03</TT
></TD
><TD
><TT
CLASS="LITERAL"
>February 1, 2003</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>1999-Jan-08</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>Jan-08-1999</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>08-Jan-1999</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>99-Jan-08</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>08-Jan-99</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>08-Jan-06</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 8, 2006</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>Jan-08-99</TT
></TD
><TD
><TT
CLASS="LITERAL"
>January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>19990108</TT
></TD
><TD
><TT
CLASS="LITERAL"
>ISO 8601; January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>990108</TT
></TD
><TD
><TT
CLASS="LITERAL"
>ISO 8601; January 8, 1999</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>1999.008</TT
></TD
><TD
><TT
CLASS="LITERAL"
>year and day of year</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>J2451187</TT
></TD
><TD
><TT
CLASS="LITERAL"
>Julian day</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>January 8, 99 BC</TT
></TD
><TD
><TT
CLASS="LITERAL"
>year 99 before the Common Era</TT
></TD
></TR
></TBODY
></TABLE
></DIV
></DD
><DT
><A
NAME="PGTYPESDATETOASC"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESdate_to_asc</CODE
></DT
><DD
><P
> Return the textual representation of a date variable.
</P><PRE
CLASS="SYNOPSIS"
>char *PGTYPESdate_to_asc(date dDate);</PRE
><P>
The function receives the date <TT
CLASS="LITERAL"
>dDate</TT
> as its only parameter.
It will output the date in the form <TT
CLASS="LITERAL"
>1999-01-18</TT
>, i.e., in the
<TT
CLASS="LITERAL"
>YYYY-MM-DD</TT
> format.
</P
></DD
><DT
><A
NAME="PGTYPESDATEJULMDY"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESdate_julmdy</CODE
></DT
><DD
><P
> Extract the values for the day, the month and the year from a variable
of type date.
</P><PRE
CLASS="SYNOPSIS"
>void PGTYPESdate_julmdy(date d, int *mdy);</PRE
><P>
The function receives the date <TT
CLASS="LITERAL"
>d</TT
> and a pointer to an array
of 3 integer values <TT
CLASS="LITERAL"
>mdy</TT
>. The variable name indicates
the sequential order: <TT
CLASS="LITERAL"
>mdy[0]</TT
> will be set to contain the
number of the month, <TT
CLASS="LITERAL"
>mdy[1]</TT
> will be set to the value of the
day and <TT
CLASS="LITERAL"
>mdy[2]</TT
> will contain the year.
</P
></DD
><DT
><A
NAME="PGTYPESDATEMDYJUL"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESdate_mdyjul</CODE
></DT
><DD
><P
> Create a date value from an array of 3 integers that specify the
day, the month and the year of the date.
</P><PRE
CLASS="SYNOPSIS"
>void PGTYPESdate_mdyjul(int *mdy, date *jdate);</PRE
><P>
The function receives the array of the 3 integers (<TT
CLASS="LITERAL"
>mdy</TT
>) as
its first argument and as its second argument a pointer to a variable
of type date that should hold the result of the operation.
</P
></DD
><DT
><A
NAME="PGTYPESDATEDAYOFWEEK"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESdate_dayofweek</CODE
></DT
><DD
><P
> Return a number representing the day of the week for a date value.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESdate_dayofweek(date d);</PRE
><P>
The function receives the date variable <TT
CLASS="LITERAL"
>d</TT
> as its only
argument and returns an integer that indicates the day of the week for
this date.
<P
></P
></P><UL
><LI
><P
> 0 - Sunday
</P
></LI
><LI
><P
> 1 - Monday
</P
></LI
><LI
><P
> 2 - Tuesday
</P
></LI
><LI
><P
> 3 - Wednesday
</P
></LI
><LI
><P
> 4 - Thursday
</P
></LI
><LI
><P
> 5 - Friday
</P
></LI
><LI
><P
> 6 - Saturday
</P
></LI
></UL
><P>
</P
></DD
><DT
><A
NAME="PGTYPESDATETODAY"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESdate_today</CODE
></DT
><DD
><P
> Get the current date.
</P><PRE
CLASS="SYNOPSIS"
>void PGTYPESdate_today(date *d);</PRE
><P>
The function receives a pointer to a date variable (<TT
CLASS="LITERAL"
>d</TT
>)
that it sets to the current date.
</P
></DD
><DT
><A
NAME="PGTYPESDATEFMTASC"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESdate_fmt_asc</CODE
></DT
><DD
><P
> Convert a variable of type date to its textual representation using a
format mask.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESdate_fmt_asc(date dDate, char *fmtstring, char *outbuf);</PRE
><P>
The function receives the date to convert (<TT
CLASS="LITERAL"
>dDate</TT
>), the
format mask (<TT
CLASS="LITERAL"
>fmtstring</TT
>) and the string that will hold the
textual representation of the date (<TT
CLASS="LITERAL"
>outbuf</TT
>).
</P
><P
> On success, 0 is returned and a negative value if an error occurred.
</P
><P
> The following literals are the field specifiers you can use:
<P
></P
></P><UL
><LI
><P
> <TT
CLASS="LITERAL"
>dd</TT
> - The number of the day of the month.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>mm</TT
> - The number of the month of the year.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>yy</TT
> - The number of the year as a two digit number.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>yyyy</TT
> - The number of the year as a four digit number.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>ddd</TT
> - The name of the day (abbreviated).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>mmm</TT
> - The name of the month (abbreviated).
</P
></LI
></UL
><P>
All other characters are copied 1:1 to the output string.
</P
><P
> <A
HREF="ecpg-pgtypes.html#ECPG-PGTYPESDATE-FMT-ASC-EXAMPLE-TABLE"
>Table 32-2</A
> indicates a few possible formats. This will give
you an idea of how to use this function. All output lines are based on
the same date: November 23, 1959.
</P
><DIV
CLASS="TABLE"
><A
NAME="ECPG-PGTYPESDATE-FMT-ASC-EXAMPLE-TABLE"
></A
><P
><B
>Table 32-2. Valid input formats for <CODE
CLASS="FUNCTION"
>PGTYPESdate_fmt_asc</CODE
></B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><THEAD
><TR
><TH
>fmt</TH
><TH
>result</TH
></TR
></THEAD
><TBODY
><TR
><TD
><TT
CLASS="LITERAL"
>mmddyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>112359</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ddmmyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>231159</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>yymmdd</TT
></TD
><TD
><TT
CLASS="LITERAL"
>591123</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>yy/mm/dd</TT
></TD
><TD
><TT
CLASS="LITERAL"
>59/11/23</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>yy mm dd</TT
></TD
><TD
><TT
CLASS="LITERAL"
>59 11 23</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>yy.mm.dd</TT
></TD
><TD
><TT
CLASS="LITERAL"
>59.11.23</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>.mm.yyyy.dd.</TT
></TD
><TD
><TT
CLASS="LITERAL"
>.11.1959.23.</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>mmm. dd, yyyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>Nov. 23, 1959</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>mmm dd yyyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>Nov 23 1959</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>yyyy dd mm</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1959 23 11</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ddd, mmm. dd, yyyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>Mon, Nov. 23, 1959</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>(ddd) mmm. dd, yyyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>(Mon) Nov. 23, 1959</TT
></TD
></TR
></TBODY
></TABLE
></DIV
></DD
><DT
><A
NAME="PGTYPESDATEDEFMTASC"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESdate_defmt_asc</CODE
></DT
><DD
><P
> Use a format mask to convert a C char* string to a value of type
date.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESdate_defmt_asc(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 (<TT
CLASS="LITERAL"
>d</TT
>), the format mask to use for
parsing the date (<TT
CLASS="LITERAL"
>fmt</TT
>) and the C char* string containing
the textual representation of the date (<TT
CLASS="LITERAL"
>str</TT
>). 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
<TT
CLASS="LITERAL"
>yy</TT
> or <TT
CLASS="LITERAL"
>yyyy</TT
> that indicate the
position of the year, <TT
CLASS="LITERAL"
>mm</TT
> to indicate the position of
the month and <TT
CLASS="LITERAL"
>dd</TT
> to indicate the position of the
day.
</P
><P
> <A
HREF="ecpg-pgtypes.html#ECPG-RDEFMTDATE-EXAMPLE-TABLE"
>Table 32-3</A
> indicates a few possible formats. This will give
you an idea of how to use this function.
</P
><DIV
CLASS="TABLE"
><A
NAME="ECPG-RDEFMTDATE-EXAMPLE-TABLE"
></A
><P
><B
>Table 32-3. Valid input formats for <CODE
CLASS="FUNCTION"
>rdefmtdate</CODE
></B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><COL><THEAD
><TR
><TH
>fmt</TH
><TH
>str</TH
><TH
>result</TH
></TR
></THEAD
><TBODY
><TR
><TD
><TT
CLASS="LITERAL"
>ddmmyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>21-2-54</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1954-02-21</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ddmmyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>2-12-54</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1954-12-02</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ddmmyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>20111954</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1954-11-20</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ddmmyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>130464</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1964-04-13</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>mmm.dd.yyyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>MAR-12-1967</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1967-03-12</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>yy/mm/dd</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1954, February 3rd</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1954-02-03</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>mmm.dd.yyyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>041269</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1969-04-12</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>yy/mm/dd</TT
></TD
><TD
><TT
CLASS="LITERAL"
>In the year 2525, in the month of July, mankind will be alive on the 28th day</TT
></TD
><TD
><TT
CLASS="LITERAL"
>2525-07-28</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>dd-mm-yy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>I said on the 28th of July in the year 2525</TT
></TD
><TD
><TT
CLASS="LITERAL"
>2525-07-28</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>mmm.dd.yyyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>9/14/58</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1958-09-14</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>yy/mm/dd</TT
></TD
><TD
><TT
CLASS="LITERAL"
>47/03/29</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1947-03-29</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>mmm.dd.yyyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>oct 28 1975</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1975-10-28</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>mmddyy</TT
></TD
><TD
><TT
CLASS="LITERAL"
>Nov 14th, 1985</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1985-11-14</TT
></TD
></TR
></TBODY
></TABLE
></DIV
></DD
></DL
></DIV
><P>
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN37409"
>32.8.3. The timestamp type</A
></H2
><P
> The timestamp type in C enables your programs to deal with data of the SQL
type timestamp. See <A
HREF="datatype-datetime.html"
>Section 8.5</A
> for the equivalent
type in the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> server.
</P
><P
> The following functions can be used to work with the timestamp type:
<P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
NAME="PGTYPESTIMESTAMPFROMASC"
></A
><CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_from_asc</CODE
></DT
><DD
><P
> Parse a timestamp from its textual representation into a timestamp
variable.
</P><PRE
CLASS="SYNOPSIS"
>timestamp PGTYPEStimestamp_from_asc(char *str, char **endptr);</PRE
><P>
The function receives the string to parse (<TT
CLASS="LITERAL"
>str</TT
>) and a
pointer to a C char* (<TT
CLASS="LITERAL"
>endptr</TT
>).
At the moment ecpg always parses
the complete string and so it currently does not support to store the
address of the first invalid character in <TT
CLASS="LITERAL"
>*endptr</TT
>.
You can safely set <TT
CLASS="LITERAL"
>endptr</TT
> to NULL.
</P
><P
> The function returns the parsed timestamp on success. On error,
<TT
CLASS="LITERAL"
>PGTYPESInvalidTimestamp</TT
> is returned and errno is
set to <TT
CLASS="LITERAL"
>PGTYPES_TS_BAD_TIMESTAMP</TT
>. See <A
HREF="ecpg-pgtypes.html#PGTYPESINVALIDTIMESTAMP"
><I
CLASS="TERM"
><TT
CLASS="LITERAL"
>PGTYPESInvalidTimestamp</TT
></I
></A
> for important notes on this value.
</P
><P
> In general, the input string can contain any combination of an allowed
date specification, a whitespace character and an allowed time
specification. Note that timezones are not supported by ecpg. It can
parse them but does not apply any calculation as the
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> server does for example. Timezone
specifiers are silently discarded.
</P
><P
> <A
HREF="ecpg-pgtypes.html#ECPG-PGTYPESTIMESTAMP-FROM-ASC-EXAMPLE-TABLE"
>Table 32-4</A
> contains a few examples for input strings.
</P
><DIV
CLASS="TABLE"
><A
NAME="ECPG-PGTYPESTIMESTAMP-FROM-ASC-EXAMPLE-TABLE"
></A
><P
><B
>Table 32-4. Valid input formats for <CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_from_asc</CODE
></B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><THEAD
><TR
><TH
>Input</TH
><TH
>Result</TH
></TR
></THEAD
><TBODY
><TR
><TD
><TT
CLASS="LITERAL"
>1999-01-08 04:05:06</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1999-01-08 04:05:06</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>January 8 04:05:06 1999 PST</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1999-01-08 04:05:06</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>1999-Jan-08 04:05:06.789-8</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1999-01-08 04:05:06.789 (time zone specifier ignored)</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>J2451187 04:05-08:00</TT
></TD
><TD
><TT
CLASS="LITERAL"
>1999-01-08 04:05:00 (time zone specifier ignored)</TT
></TD
></TR
></TBODY
></TABLE
></DIV
></DD
><DT
><A
NAME="PGTYPESTIMESTAMPTOASC"
></A
><CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_to_asc</CODE
></DT
><DD
><P
> Converts a date to a C char* string.
</P><PRE
CLASS="SYNOPSIS"
>char *PGTYPEStimestamp_to_asc(timestamp tstamp);</PRE
><P>
The function receives the timestamp <TT
CLASS="LITERAL"
>tstamp</TT
> as
its only argument and returns an allocated string that contains the
textual representation of the timestamp.
</P
></DD
><DT
><A
NAME="PGTYPESTIMESTAMPCURRENT"
></A
><CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_current</CODE
></DT
><DD
><P
> Retrieve the current timestamp.
</P><PRE
CLASS="SYNOPSIS"
>void PGTYPEStimestamp_current(timestamp *ts);</PRE
><P>
The function retrieves the current timestamp and saves it into the
timestamp variable that <TT
CLASS="LITERAL"
>ts</TT
> points to.
</P
></DD
><DT
><A
NAME="PGTYPESTIMESTAMPFMTASC"
></A
><CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_fmt_asc</CODE
></DT
><DD
><P
> Convert a timestamp variable to a C char* using a format mask.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPEStimestamp_fmt_asc(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 (<TT
CLASS="LITERAL"
>ts</TT
>), a pointer to the output buffer
(<TT
CLASS="LITERAL"
>output</TT
>), the maximal length that has been allocated for
the output buffer (<TT
CLASS="LITERAL"
>str_len</TT
>) and the format mask to
use for the conversion (<TT
CLASS="LITERAL"
>fmtstr</TT
>).
</P
><P
> Upon success, the function returns 0 and a negative value if an
error occurred.
</P
><P
> You can use the following format specifiers for the format mask. The
format specifiers are the same ones that are used in the
<CODE
CLASS="FUNCTION"
>strftime</CODE
> function in <SPAN
CLASS="PRODUCTNAME"
>libc</SPAN
>. Any
non-format specifier will be copied into the output buffer.
<P
></P
></P><UL
><LI
><P
> <TT
CLASS="LITERAL"
>%A</TT
> - is replaced by national representation of
the full weekday name.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%a</TT
> - is replaced by national representation of
the abbreviated weekday name.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%B</TT
> - is replaced by national representation of
the full month name.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%b</TT
> - is replaced by national representation of
the abbreviated month name.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%C</TT
> - is replaced by (year / 100) as decimal
number; single digits are preceded by a zero.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%c</TT
> - is replaced by national representation of
time and date.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%D</TT
> - is equivalent to
<TT
CLASS="LITERAL"
>%m/%d/%y</TT
>.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%d</TT
> - is replaced by the day of the month as a
decimal number (01-31).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%E*</TT
> <TT
CLASS="LITERAL"
>%O*</TT
> - POSIX locale
extensions. The sequences
<TT
CLASS="LITERAL"
>%Ec</TT
>
<TT
CLASS="LITERAL"
>%EC</TT
>
<TT
CLASS="LITERAL"
>%Ex</TT
>
<TT
CLASS="LITERAL"
>%EX</TT
>
<TT
CLASS="LITERAL"
>%Ey</TT
>
<TT
CLASS="LITERAL"
>%EY</TT
>
<TT
CLASS="LITERAL"
>%Od</TT
>
<TT
CLASS="LITERAL"
>%Oe</TT
>
<TT
CLASS="LITERAL"
>%OH</TT
>
<TT
CLASS="LITERAL"
>%OI</TT
>
<TT
CLASS="LITERAL"
>%Om</TT
>
<TT
CLASS="LITERAL"
>%OM</TT
>
<TT
CLASS="LITERAL"
>%OS</TT
>
<TT
CLASS="LITERAL"
>%Ou</TT
>
<TT
CLASS="LITERAL"
>%OU</TT
>
<TT
CLASS="LITERAL"
>%OV</TT
>
<TT
CLASS="LITERAL"
>%Ow</TT
>
<TT
CLASS="LITERAL"
>%OW</TT
>
<TT
CLASS="LITERAL"
>%Oy</TT
>
are supposed to provide alternative representations.
</P
><P
> Additionally <TT
CLASS="LITERAL"
>%OB</TT
> implemented to represent
alternative months names (used standalone, without day mentioned).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%e</TT
> - is replaced by the day of month as a decimal
number (1-31); single digits are preceded by a blank.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%F</TT
> - is equivalent to <TT
CLASS="LITERAL"
>%Y-%m-%d</TT
>.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%G</TT
> - is replaced by a year as a decimal number
with century. This year is the one that contains the greater part of
the week (Monday as the first day of the week).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%g</TT
> - is replaced by the same year as in
<TT
CLASS="LITERAL"
>%G</TT
>, but as a decimal number without century
(00-99).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%H</TT
> - is replaced by the hour (24-hour clock) as a
decimal number (00-23).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%h</TT
> - the same as <TT
CLASS="LITERAL"
>%b</TT
>.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%I</TT
> - is replaced by the hour (12-hour clock) as a
decimal number (01-12).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%j</TT
> - is replaced by the day of the year as a
decimal number (001-366).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%k</TT
> - is replaced by the hour (24-hour clock) as a
decimal number (0-23); single digits are preceded by a blank.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%l</TT
> - is replaced by the hour (12-hour clock) as a
decimal number (1-12); single digits are preceded by a blank.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%M</TT
> - is replaced by the minute as a decimal
number (00-59).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%m</TT
> - is replaced by the month as a decimal number
(01-12).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%n</TT
> - is replaced by a newline.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%O*</TT
> - the same as <TT
CLASS="LITERAL"
>%E*</TT
>.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%p</TT
> - is replaced by national representation of
either "ante meridiem" or "post meridiem" as appropriate.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%R</TT
> - is equivalent to <TT
CLASS="LITERAL"
>%H:%M</TT
>.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%r</TT
> - is equivalent to <TT
CLASS="LITERAL"
>%I:%M:%S
%p</TT
>.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%S</TT
> - is replaced by the second as a decimal
number (00-60).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%s</TT
> - is replaced by the number of seconds since
the Epoch, UTC.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%T</TT
> - is equivalent to <TT
CLASS="LITERAL"
>%H:%M:%S</TT
>
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%t</TT
> - is replaced by a tab.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%U</TT
> - is replaced by the week number of the year
(Sunday as the first day of the week) as a decimal number (00-53).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%u</TT
> - is replaced by the weekday (Monday as the
first day of the week) as a decimal number (1-7).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%V</TT
> - is replaced by the week number of the year
(Monday as the first day of the week) as a decimal number (01-53).
If the week containing January 1 has four or more days in the new
year, then it is week 1; otherwise it is the last week of the
previous year, and the next week is week 1.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%v</TT
> - is equivalent to
<TT
CLASS="LITERAL"
>%e-%b-%Y</TT
>.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%W</TT
> - is replaced by the week number of the year
(Monday as the first day of the week) as a decimal number (00-53).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%w</TT
> - is replaced by the weekday (Sunday as the
first day of the week) as a decimal number (0-6).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%X</TT
> - is replaced by national representation of
the time.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%x</TT
> - is replaced by national representation of
the date.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%Y</TT
> - is replaced by the year with century as a
decimal number.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%y</TT
> - is replaced by the year without century as a
decimal number (00-99).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%Z</TT
> - is replaced by the time zone name.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%z</TT
> - is replaced by the time zone offset from
UTC; a leading plus sign stands for east of UTC, a minus sign for
west of UTC, hours and minutes follow with two digits each and no
delimiter between them (common form for RFC 822 date headers).
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%+</TT
> - is replaced by national representation of
the date and time.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%-*</TT
> - GNU libc extension. Do not do any padding
when performing numerical outputs.
</P
></LI
><LI
><P
> $_* - GNU libc extension. Explicitly specify space for padding.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%0*</TT
> - GNU libc extension. Explicitly specify zero
for padding.
</P
></LI
><LI
><P
> <TT
CLASS="LITERAL"
>%%</TT
> - is replaced by <TT
CLASS="LITERAL"
>%</TT
>.
</P
></LI
></UL
><P>
</P
></DD
><DT
><A
NAME="PGTYPESTIMESTAMPSUB"
></A
><CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_sub</CODE
></DT
><DD
><P
> Subtract one timestamp from another one and save the result in a
variable of type interval.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPEStimestamp_sub(timestamp *ts1, timestamp *ts2, interval *iv);</PRE
><P>
The function will subtract the timestamp variable that <TT
CLASS="LITERAL"
>ts2</TT
>
points to from the timestamp variable that <TT
CLASS="LITERAL"
>ts1</TT
> points to
and will store the result in the interval variable that <TT
CLASS="LITERAL"
>iv</TT
>
points to.
</P
><P
> Upon success, the function returns 0 and a negative value if an
error occurred.
</P
></DD
><DT
><A
NAME="PGTYPESTIMESTAMPDEFMTASC"
></A
><CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_defmt_asc</CODE
></DT
><DD
><P
> Parse a timestamp value from its textual representation using a
formatting mask.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPEStimestamp_defmt_asc(char *str, char *fmt, timestamp *d);</PRE
><P>
The function receives the textual representation of a timestamp in the
variable <TT
CLASS="LITERAL"
>str</TT
> as well as the formatting mask to use in the
variable <TT
CLASS="LITERAL"
>fmt</TT
>. The result will be stored in the variable
that <TT
CLASS="LITERAL"
>d</TT
> points to.
</P
><P
> If the formatting mask <TT
CLASS="LITERAL"
>fmt</TT
> is NULL, the function will fall
back to the default formatting mask which is <TT
CLASS="LITERAL"
>%Y-%m-%d
%H:%M:%S</TT
>.
</P
><P
> This is the reverse function to <A
HREF="ecpg-pgtypes.html#PGTYPESTIMESTAMPFMTASC"
><I
CLASS="TERM"
><CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_fmt_asc</CODE
></I
></A
>. See the documentation there in
order to find out about the possible formatting mask entries.
</P
></DD
><DT
><A
NAME="PGTYPESTIMESTAMPADDINTERVAL"
></A
><CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_add_interval</CODE
></DT
><DD
><P
> Add an interval variable to a timestamp variable.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPEStimestamp_add_interval(timestamp *tin, interval *span, timestamp *tout);</PRE
><P>
The function receives a pointer to a timestamp variable <TT
CLASS="LITERAL"
>tin</TT
>
and a pointer to an interval variable <TT
CLASS="LITERAL"
>span</TT
>. It adds the
interval to the timestamp and saves the resulting timestamp in the
variable that <TT
CLASS="LITERAL"
>tout</TT
> points to.
</P
><P
> Upon success, the function returns 0 and a negative value if an
error occurred.
</P
></DD
><DT
><A
NAME="PGTYPESTIMESTAMPSUBINTERVAL"
></A
><CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_sub_interval</CODE
></DT
><DD
><P
> Subtract an interval variable from a timestamp variable.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPEStimestamp_sub_interval(timestamp *tin, interval *span, timestamp *tout);</PRE
><P>
The function subtracts the interval variable that <TT
CLASS="LITERAL"
>span</TT
>
points to from the timestamp variable that <TT
CLASS="LITERAL"
>tin</TT
> points to
and saves the result into the variable that <TT
CLASS="LITERAL"
>tout</TT
> points
to.
</P
><P
> Upon success, the function returns 0 and a negative value if an
error occurred.
</P
></DD
></DL
></DIV
><P>
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN37708"
>32.8.4. The interval type</A
></H2
><P
> The interval type in C enables your programs to deal with data of the SQL
type interval. See <A
HREF="datatype-datetime.html"
>Section 8.5</A
> for the equivalent
type in the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> server.
</P
><P
> The following functions can be used to work with the interval type:
<P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
NAME="PGTYPESINTERVALNEW"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESinterval_new</CODE
></DT
><DD
><P
> Return a pointer to a newly allocated interval variable.
</P><PRE
CLASS="SYNOPSIS"
>interval *PGTYPESinterval_new(void);</PRE
><P>
</P
></DD
><DT
><A
NAME="PGTYPESINTERVALFREE"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESinterval_free</CODE
></DT
><DD
><P
> Release the memory of a previously allocated interval variable.
</P><PRE
CLASS="SYNOPSIS"
>void PGTYPESinterval_new(interval *intvl);</PRE
><P>
</P
></DD
><DT
><A
NAME="PGTYPESINTERVALFROMASC"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESinterval_from_asc</CODE
></DT
><DD
><P
> Parse an interval from its textual representation.
</P><PRE
CLASS="SYNOPSIS"
>interval *PGTYPESinterval_from_asc(char *str, char **endptr);</PRE
><P>
The function parses the input string <TT
CLASS="LITERAL"
>str</TT
> and returns a
pointer to an allocated interval variable.
At the moment ecpg always parses
the complete string and so it currently does not support to store the
address of the first invalid character in <TT
CLASS="LITERAL"
>*endptr</TT
>.
You can safely set <TT
CLASS="LITERAL"
>endptr</TT
> to NULL.
</P
></DD
><DT
><A
NAME="PGTYPESINTERVALTOASC"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESinterval_to_asc</CODE
></DT
><DD
><P
> Convert a variable of type interval to its textual representation.
</P><PRE
CLASS="SYNOPSIS"
>char *PGTYPESinterval_to_asc(interval *span);</PRE
><P>
The function converts the interval variable that <TT
CLASS="LITERAL"
>span</TT
>
points to into a C char*. The output looks like this example:
<TT
CLASS="LITERAL"
>@ 1 day 12 hours 59 mins 10 secs</TT
>.
</P
></DD
><DT
><A
NAME="PGTYPESINTERVALCOPY"
></A
><CODE
CLASS="FUNCTION"
>PGTYPESinterval_copy</CODE
></DT
><DD
><P
> Copy a variable of type interval.
</P><PRE
CLASS="SYNOPSIS"
>int PGTYPESinterval_copy(interval *intvlsrc, interval *intvldest);</PRE
><P>
The function copies the interval variable that <TT
CLASS="LITERAL"
>intvlsrc</TT
>
points to into the variable that <TT
CLASS="LITERAL"
>intvldest</TT
> points to. Note
that you need to allocate the memory for the destination variable
before.
</P
></DD
></DL
></DIV
><P>
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN37752"
>32.8.5. The decimal type</A
></H2
><P
> The decimal type is similar to the numeric type. However it is limited to
a maximal precision of 30 significant digits. In contrast to the numeric
type which can be created on the heap only, the decimal type can be
created either on the stack or on the heap (by means of the functions
PGTYPESdecimal_new() and PGTYPESdecimal_free(). There are a lot of other
functions that deal with the decimal type in the <SPAN
CLASS="PRODUCTNAME"
>Informix</SPAN
> compatibility
mode described in <A
HREF="ecpg-informix-compat.html"
>Section 32.9</A
>.
</P
><P
> The following functions can be used to work with the decimal type and are
not only contained in the <TT
CLASS="LITERAL"
>libcompat</TT
> library.
<P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESdecimal_new</CODE
></DT
><DD
><P
> Request a pointer to a newly allocated decimal variable.
</P><PRE
CLASS="SYNOPSIS"
>decimal *PGTYPESdecimal_new(void);</PRE
><P>
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>PGTYPESdecimal_free</CODE
></DT
><DD
><P
> Free a decimal type, release all of its memory.
</P><PRE
CLASS="SYNOPSIS"
>void PGTYPESdecimal_free(decimal *var);</PRE
><P>
</P
></DD
></DL
></DIV
><P>
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN37772"
>32.8.6. errno values of pgtypeslib</A
></H2
><P
> <P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="LITERAL"
>PGTYPES_NUM_BAD_NUMERIC</TT
></DT
><DD
><P
> An argument should contain a numeric variable (or point to a numeric
variable) but in fact its in-memory representation was invalid.
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_NUM_OVERFLOW</TT
></DT
><DD
><P
> An overflow occurred. Since the numeric type can deal with almost
arbitrary precision, converting a numeric variable into other types
might cause overflow.
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_NUM_OVERFLOW</TT
></DT
><DD
><P
> An underflow occurred. Since the numeric type can deal with almost
arbitrary precision, converting a numeric variable into other types
might cause underflow.
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_NUM_DIVIDE_ZERO</TT
></DT
><DD
><P
> A division by zero has been attempted.
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_DATE_BAD_DATE</TT
></DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_DATE_ERR_EARGS</TT
></DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_DATE_ERR_ENOSHORTDATE</TT
></DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_INTVL_BAD_INTERVAL</TT
></DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_DATE_ERR_ENOTDMY</TT
></DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_DATE_BAD_DAY</TT
></DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_DATE_BAD_MONTH</TT
></DT
><DD
><P
>
</P
></DD
><DT
><TT
CLASS="LITERAL"
>PGTYPES_TS_BAD_TIMESTAMP</TT
></DT
><DD
><P
>
</P
></DD
></DL
></DIV
><P>
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN37836"
>32.8.7. Special constants of pgtypeslib</A
></H2
><P
> <P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
NAME="PGTYPESINVALIDTIMESTAMP"
></A
><TT
CLASS="LITERAL"
>PGTYPESInvalidTimestamp</TT
></DT
><DD
><P
> A value of type timestamp representing an invalid time stamp. This is
returned by the function <CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_from_asc</CODE
> on
parse error.
Note that due to the internal representation of the timestamp datatype,
<TT
CLASS="LITERAL"
>PGTYPESInvalidTimestamp</TT
> is also a valid timestamp at
the same time. It is set to <TT
CLASS="LITERAL"
>1899-12-31 23:59:59</TT
>. In order
to detect errors, make sure that your application does not only test
for <TT
CLASS="LITERAL"
>PGTYPESInvalidTimestamp</TT
> but also for
<TT
CLASS="LITERAL"
>errno != 0</TT
> after each call to
<CODE
CLASS="FUNCTION"
>PGTYPEStimestamp_from_asc</CODE
>.
</P
></DD
></DL
></DIV
><P>
</P
></DIV
></DIV
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