your passing the wrong type to printf. you need to pass a pointer to a string and your currently passing a char or really a int since char is typedef; enable warnings when compiling eg: gcc -Wall. also add #include <stdio.h> at the top of your source file
I have a program which I wish to modify. It used to be run from the command line, but now I wish to change this so it can be used as a function.
The program has complex argument processing so I want to pass my paramters to as if it were being called by the OS as a program.
I have tried to... (2 Replies)
I searched on the forums. No advises.
I am using a previous source code. I changed the main function main(int argc, char **argv) in a function misc(int argc, char **argv). How do you use the argc and argv parameters? This is how I am calling the function :
char param;
strcat(param,"wgrib ");... (4 Replies)
I have a script that asks a bunch of questions using the following method for input:
print "Name:";
while(<>){
chomp;
$name=$_;
}
So for example, if the questions asked for name, age, & color (in that order)... I want to be able to easily convert $ARGV into the input expected by... (2 Replies)
Hi C experts,
I have the following code for adding command line option for a program
int main (argc, argv)
int argc;
char *argv;
{
char *mem_type; //memory type
char *name; //name of the memory
int addr; //address bits
int data; ... (5 Replies)
this is in one of my scripts...
if ($#argv == 0) then
echo 'blah bla'
exit 0
endif
I want it to be something like this...
if ($#argv == 0 OR $argv >=3)
echo 'blah bla'
exit 0
endif
so when the arguments are none, or greater than three I want this "if then" to take over. how? I... (5 Replies)
Hello all,
Had a quick question:
In a typical csh script should inputting via stdin (i.e. set i = $< ) increase the value of $#argv ?
echo enter an value:
set val= "$<"
if($#argv == 0) then
echo No args
else
echo The arg is $argv
so if a value is inputted #argv... (1 Reply)
I'm working on my own pow function and I need to make a copy of *argv but
I think that I am having trouble with the size of *argv and the size of any array that I
make. The code below isn't working for me. and I want to accept any number no
matter the size with pow -f 2 2. I was working out... (16 Replies)
All of my machines (various open source derivatives on x86 and amd64) store argv above the stack (at a higher memory address). I am curious to learn if any systems store argv below the stack (at a lower memory address).
I am particularly interested in proprietary Unices, such as Solaris, HP-UX,... (9 Replies)
So i am trying to read in file
readFile <GivenFile> modFile
looking for a regular file under the directories in the GivenFile and print them out is my over all goal.
basically I am looking for anything that looks like a directory in the given file and printing it out.
Since I am trying to do... (2 Replies)
Discussion started by: squidGreen
2 Replies
LEARN ABOUT REDHAT
varargs
varargs(3EXT) Extended Library Functions varargs(3EXT)NAME
varargs - handle variable argument list
SYNOPSIS
#include <varargs.h>
va_alist
va_dcl
va_list pvar;
void va_start(va_listpvar);
type va_arg(va_list pvar, type);
void va_end(va_list pvar);
DESCRIPTION
This set of macros allows portable procedures that accept variable argument lists to be written. Routines that have variable argument lists
(such as printf(3C)) but do not use varargs are inherently non-portable, as different machines use different argument-passing conventions.
va_alist is used as the parameter list in a function header.
va_dcl is a declaration for va_alist. No semicolon should follow va_dcl.
va_list is a type defined for the variable used to traverse the list.
va_start is called to initialize pvar to the beginning of the list.
va_arg will return the next argument in the list pointed to by pvar. type is the type the argument is expected to be. Different types can
be mixed, but it is up to the routine to know what type of argument is expected, as it cannot be determined at runtime.
va_end is used to clean up.
Multiple traversals, each bracketed by va_start and va_end, are possible.
EXAMPLES
Example 1: A sample program.
This example is a possible implementation of execl (see exec(2) ).
#include <unistd.h>
#include <varargs.h>
#define MAXARGS 100
/* execl is called by
execl(file, arg1, arg2, ..., (char *)0);
*/
execl(va_alist)
va_dcl
{
va_list ap;
char *file;
char *args[MAXARGS]; /* assumed big enough*/
int argno = 0;
va_start(ap);
file = va_arg(ap, char *);
while ((args[argno++] = va_arg(ap, char *)) != 0)
;
va_end(ap);
return execv(file, args);
}
SEE ALSO exec(2), printf(3C), vprintf(3C), stdarg(3EXT)NOTES
It is up to the calling routine to specify in some manner how many arguments there are, since it is not always possible to determine the
number of arguments from the stack frame. For example, execl is passed a zero pointer to signal the end of the list. printf can tell how
many arguments are there by the format.
It is non-portable to specify a second argument of char, short, or float to va_arg, since arguments seen by the called function are not
char, short, or float. C converts char and short arguments to int and converts float arguments to double before passing them to a function.
stdarg is the preferred interface.
SunOS 5.10 10 May 2002 varargs(3EXT)