<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >pgtypes Library</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 9.2.5 Documentation" HREF="index.html"><LINK REL="UP" TITLE="ECPG - Embedded SQL in C" HREF="ecpg.html"><LINK REL="PREVIOUS" TITLE="Dynamic SQL" HREF="ecpg-dynamic.html"><LINK REL="NEXT" TITLE="Using Descriptor Areas" HREF="ecpg-descriptors.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2013-10-08T03:47:12"></HEAD ><BODY CLASS="SECT1" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" ><A HREF="index.html" >PostgreSQL 9.2.5 Documentation</A ></TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A TITLE="Dynamic SQL" HREF="ecpg-dynamic.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="ecpg.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" >Chapter 33. <SPAN CLASS="APPLICATION" >ECPG</SPAN > - Embedded <ACRONYM CLASS="ACRONYM" >SQL</ACRONYM > in C</TD ><TD WIDTH="20%" ALIGN="right" VALIGN="top" ><A TITLE="Using Descriptor Areas" HREF="ecpg-descriptors.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="ECPG-PGTYPES" >33.6. 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="ECPG-PGTYPES-NUMERIC" >33.6.1. 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 numeric 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 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="ECPG-PGTYPES-DATE" >33.6.2. 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 33-2</A > shows the allowed input formats. </P ><DIV CLASS="TABLE" ><A NAME="ECPG-PGTYPESDATE-FROM-ASC-TABLE" ></A ><P ><B >Table 33-2. 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 33-3</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 33-3. Valid Input Formats for <CODE CLASS="FUNCTION" >PGTYPESdate_fmt_asc</CODE ></B ></P ><TABLE BORDER="1" CLASS="CALSTABLE" ><COL><COL><THEAD ><TR ><TH >Format</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 <TT CLASS="TYPE" >char*</TT > 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 33-4</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 33-4. Valid Input Formats for <CODE CLASS="FUNCTION" >rdefmtdate</CODE ></B ></P ><TABLE BORDER="1" CLASS="CALSTABLE" ><COL><COL><COL><THEAD ><TR ><TH >Format</TH ><TH >String</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="ECPG-PGTYPES-TIMESTAMP" >33.6.3. 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 <TT CLASS="VARNAME" >errno</TT > 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 time zones 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 33-5</A > contains a few examples for input strings. </P ><DIV CLASS="TABLE" ><A NAME="ECPG-PGTYPESTIMESTAMP-FROM-ASC-EXAMPLE-TABLE" ></A ><P ><B >Table 33-5. 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 <SPAN CLASS="QUOTE" >"ante meridiem"</SPAN > or <SPAN CLASS="QUOTE" >"post meridiem"</SPAN > 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="ECPG-PGTYPES-INTERVAL" >33.6.4. 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="ECPG-PGTYPES-DECIMAL" >33.6.5. The decimal Type</A ></H2 ><P > The decimal type is similar to the numeric type. However it is limited to a maximum 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 <CODE CLASS="FUNCTION" >PGTYPESdecimal_new</CODE > and <CODE CLASS="FUNCTION" >PGTYPESdecimal_free</CODE >). 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 33.15</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="ECPG-PGTYPES-ERRNO" >33.6.6. 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_UNDERFLOW</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 > An invalid date string was passed to the <CODE CLASS="FUNCTION" >PGTYPESdate_from_asc</CODE > function. </P ></DD ><DT ><TT CLASS="LITERAL" >PGTYPES_DATE_ERR_EARGS</TT ></DT ><DD ><P > Invalid arguments were passed to the <CODE CLASS="FUNCTION" >PGTYPESdate_defmt_asc</CODE > function. </P ></DD ><DT ><TT CLASS="LITERAL" >PGTYPES_DATE_ERR_ENOSHORTDATE</TT ></DT ><DD ><P > An invalid token in the input string was found by the <CODE CLASS="FUNCTION" >PGTYPESdate_defmt_asc</CODE > function. </P ></DD ><DT ><TT CLASS="LITERAL" >PGTYPES_INTVL_BAD_INTERVAL</TT ></DT ><DD ><P > An invalid interval string was passed to the <CODE CLASS="FUNCTION" >PGTYPESinterval_from_asc</CODE > function, or an invalid interval value was passed to the <CODE CLASS="FUNCTION" >PGTYPESinterval_to_asc</CODE > function. </P ></DD ><DT ><TT CLASS="LITERAL" >PGTYPES_DATE_ERR_ENOTDMY</TT ></DT ><DD ><P > There was a mismatch in the day/month/year assignment in the <CODE CLASS="FUNCTION" >PGTYPESdate_defmt_asc</CODE > function. </P ></DD ><DT ><TT CLASS="LITERAL" >PGTYPES_DATE_BAD_DAY</TT ></DT ><DD ><P > An invalid day of the month value was found by the <CODE CLASS="FUNCTION" >PGTYPESdate_defmt_asc</CODE > function. </P ></DD ><DT ><TT CLASS="LITERAL" >PGTYPES_DATE_BAD_MONTH</TT ></DT ><DD ><P > An invalid month value was found by the <CODE CLASS="FUNCTION" >PGTYPESdate_defmt_asc</CODE > function. </P ></DD ><DT ><TT CLASS="LITERAL" >PGTYPES_TS_BAD_TIMESTAMP</TT ></DT ><DD ><P > An invalid timestamp string pass passed to the <CODE CLASS="FUNCTION" >PGTYPEStimestamp_from_asc</CODE > function, or an invalid timestamp value was passed to the <CODE CLASS="FUNCTION" >PGTYPEStimestamp_to_asc</CODE > function. </P ></DD ><DT ><TT CLASS="LITERAL" >PGTYPES_TS_ERR_EINFTIME</TT ></DT ><DD ><P > An infinite timestamp value was encountered in a context that cannot handle it. </P ></DD ></DL ></DIV ><P> </P ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="ECPG-PGTYPES-CONSTANTS" >33.6.7. 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 <TT CLASS="TYPE" >timestamp</TT > data type, <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 ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="ecpg-dynamic.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="ecpg-descriptors.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Dynamic SQL</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ecpg.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Using Descriptor Areas</TD ></TR ></TABLE ></DIV ></BODY ></HTML >