summaryrefslogtreecommitdiff
path: root/reference/C/MAN/va_start.htm
diff options
context:
space:
mode:
authorTobias Klauser <tklauser@distanz.ch>2008-01-27 11:37:44 +0100
committerTobias Klauser <tklauser@xenon.tklauser.home>2008-01-27 11:37:44 +0100
commit7e0f021a9aec35fd8e6725e87e3313b101d26f5e (patch)
treeb1cacc4b24393f517aeb4610e9e1021f954307a8 /reference/C/MAN/va_start.htm
Initial import (2.0.2-6)2.0.2-6
Diffstat (limited to 'reference/C/MAN/va_start.htm')
-rw-r--r--reference/C/MAN/va_start.htm159
1 files changed, 159 insertions, 0 deletions
diff --git a/reference/C/MAN/va_start.htm b/reference/C/MAN/va_start.htm
new file mode 100644
index 0000000..a35845f
--- /dev/null
+++ b/reference/C/MAN/va_start.htm
@@ -0,0 +1,159 @@
+<TITLE>va_start</TITLE>
+<body bgcolor="#ffffcc">
+<hr>
+<pre>
+
+
+
+<h3>STDARG(3) Linux Programmer's Manual STDARG(3)
+</h3>
+
+<h3>NAME
+</h3> stdarg - variable argument lists
+
+<h3>SYNOPSIS
+</h3> #include &lt;stdarg.h&gt;
+
+ void va_start( va_list ap, last);
+ typeva_arg( va_list ap, type);
+ void va_end( va_list ap);
+
+<h3>DESCRIPTION
+</h3> A function may be called with a varying number of argu-
+ ments of varying types. The include file stdarg.h
+ declares a type va_list and defines three macros for step-
+ ping through a list of arguments whose number and types
+ are not known to the called function.
+
+ The called function must declare an object of type va_list
+ which is used by the macros va_start, va_arg, and va_end.
+
+ The va_start macro initializes ap for subsequent use by
+ va_arg and va_end, and must be called first.
+
+ The parameter last is the name of the last parameter
+ before the variable argument list, i.e., the last parame-
+ ter of which the calling function knows the type.
+
+ Because the address of this parameter is used in the
+ va_start macro, it should not be declared as a register
+ variable, or as a function or an array type.
+
+ The va_start macro returns no value.
+
+ The va_arg macro expands to an expression that has the
+ type and value of the next argument in the call. The
+ parameter ap is the va_list ap initialized by va_start.
+ Each call to va_arg modifies ap so that the next call
+ returns the next argument. The parameter type is a type
+ name specified so that the type of a pointer to an object
+ that has the specified type can be obtained simply by
+ adding a * to type.
+
+ If there is no next argument, or if type is not compatible
+ with the type of the actual next argument (as promoted
+ according to the default argument promotions), random
+ errors will occur.
+
+ The first use of the va_arg macro after that of the
+ va_start macro returns the argument after last. Succes-
+ sive invocations return the values of the remaining argu-
+ ments.
+
+ The va_end macro handles a normal return from the function
+ whose variable argument list was initialized by va_start.
+
+
+
+<h3>BSD MANPAGE 29 November 1993 1
+</h3>
+
+
+
+
+<h3>STDARG(3) Linux Programmer's Manual STDARG(3)
+</h3>
+
+ The va_end macro returns no value.
+
+<h3>EXAMPLES
+</h3> The function foo takes a string of format characters and
+ prints out the argument associated with each format char-
+ acter based on the type.
+ void foo(char *fmt, ...)
+ {
+ va_list ap;
+ int d;
+ char c, *p, *s;
+
+ va_start(ap, fmt);
+ while (*fmt)
+ switch(*fmt++) {
+ case 's': /* string */
+ s = va_arg(ap, char *);
+ printf("string %s\n", s);
+ break;
+ case 'd': /* int */
+ d = va_arg(ap, int);
+ printf("int %d\n", d);
+ break;
+ case 'c': /* char */
+ c = va_arg(ap, char);
+ printf("char %c\n", c);
+ break;
+ }
+ va_end(ap);
+ }
+
+<h3>STANDARDS
+</h3> The va_start, va_arg, and va_end macros conform to ANSI
+ C3.159-1989 (``ANSI C'').
+
+<h3>COMPATIBILITY
+</h3> These macros are not compatible with the historic macros
+ they replace. A backward compatible version can be found
+ in the include file varargs.h.
+
+<h3>BUGS
+</h3> Unlike the varargs macros, the stdarg macros do not permit
+ programmers to code a function with no fixed arguments.
+ This problem generates work mainly when converting varargs
+ code to stdarg code, but it also creates difficulties for
+ variadic functions that wish to pass all of their argu-
+ ments on to a function that takes a va_list argument, such
+ as vfprintf(3).
+
+
+
+
+
+
+
+
+
+<h3>BSD MANPAGE 29 November 1993 2
+</h3>
+
+ </pre>
+<P>
+<hr>
+<p>
+<center>
+<table border=2 width=80%>
+<tr align=center>
+<td width=25%>
+<a href=../cref.html>Top</a>
+</td><td width=25%>
+<a href=../master_index.html>Master Index</a>
+</td><td width=25%>
+<a href=../SYNTAX/keywords.html>Keywords</a>
+</td><td width=25%>
+<a href=../FUNCTIONS/funcref.htm>Functions</a>
+</td>
+</tr>
+</table>
+</center>
+<p>
+<hr>
+
+This manual page was brought to you by <i>mjl_man V-2.0</i>