hi,
how does a program know whether some data are available from stdin?
I would like to make a program which could read its data from stdin
and _if_there_is_nothing_at_stdin_ from a file which name is given
as an argument. If there is nothing in stdin and no filename is given as
argument,... (2 Replies)
hello all,
I need to create a password change utility for a database. I need to gather at the command line the username, password and database sid. I have the program currently doing this. What I would like to do is not have the new password appear on the screen when I do my read command.... (2 Replies)
Howdie everyone...
I have a shell script RemoveFiles.sh
Inside this file, it only has two commands as below:
rm -f ../../reportToday/temp/*
rm -f ../../report/*
My problem is that when i execute this script, nothing happened. Files remained unremoved. I don't see any error message as it... (2 Replies)
can you redirect STDIN with command arguments?
I have tried this approach:
# ./script -option <argument1> <argument2> 0<$2
# $2: ambiguous redirect
Is this possible? (4 Replies)
Hi,
Program A: uses pipe()
I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using:
* child
-> dup2(fd, STDOUT_FILENO);
-> execl("/path/PROGRAM B", "PROGRAM B", NULL);
* parent
-> char line;
-> read(fd, line, 100);
Question:
---------... (1 Reply)
Hi,
Program A: uses pipe()
I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using:
* child
-> dup2(fd, STDOUT_FILENO);
-> execl("/path/PROGRAM B", "PROGRAM B", NULL);
* parent
-> char line;
-> read(fd, line, 100);
Question:
---------... (3 Replies)
When a process fork(), the child share the same file descriptors as his father. Thus, they share the same stdin. Quick and dirty exemple below (sorry for the ugly gets() call) :
#include <stdio.h>
#include <unistd.h>
int main()
{
char buf;
if (fork()) { /*parent */
... (1 Reply)
Bonjour,
Mon application en C sous linux tourne en redirigeant stdin vers un fichier.
Exemple; $appli1 <file1.
PB: Je voudrais temporairement redonner la main au user sur le clavier.
Alors je pensais ajouter system("appli2"); dans appli1.
Dans son main() , appli2() fait seulement un... (1 Reply)
Hi,
I has the following command in the script. This command works fine if I execute on command prompt. If I run the script, this is not working as expected (deleting CR).
tr -d "\015" < ${FilePath}/${FileName} > ${FilePath}/${File_Prefix}.csv
I could not figure out whats... (6 Replies)
hi all. and sorry for the random question, but this sparkled a raging flame-war at work and i want more points of view
situation
a router, with linux of some sort,
dhcp client requesting for ip in wan1 (as usual with wan ports)
dhcp server listening in lan1, and assigning ip (as usual... (9 Replies)
Discussion started by: broli
9 Replies
LEARN ABOUT ULTRIX
sscanf
scanf(3int)scanf(3int)Name
scanf, fscanf, sscanf - convert formatted input
Syntax
#include <stdio.h>
int scanf( format [, pointer ] ... )
char *format;
int fscanf( stream, format [, pointer ] ... )
FILE *stream;
char *format;
int sscanf( s, format [, pointer ] ... )
char *s, *format;
Description
The international functions and are similar to the standard I/O functions. The difference is that the international functions allow you to
use the %digit$ conversion character in place of the I% character you use in the standard I/O functions. The digit is a decimal digit n
from 1 to 9. The international functions apply conversions to the n th argument in the argument list, rather than to the next unused argu-
ment.
You can use % conversion character in the international functions. However, you cannot mix the % conversion character with the %digit$
conversion character in a single call.
In all cases, uses the radix character and collating sequence that is defined by the last successful call to category or If the radix or
collating sequence is undefined, the function uses the C locale definitions.
International Environment
LC_COLLATE Contains the user requirements for language, territory, and codeset for the character collation format. affects the behav-
ior of regular expressions and the string collation functions in If is not defined in the current environment, provides the
necessary default.
LC_NUMERIC If this environment is set and valid, uses the international language database named in the definition to determine radix
character rules.
LANG If this environment variable is set and valid uses the international language database named in the definition to determine
collation and character classification rules. If or is defined, their definitions supersede the definition of LANG.
Examples
The following shows an example of using the function:
scanf("%2$s %1$d", integer, string)
If the input is `` january 9 '', the function assigns 9 to and ``january'' to
Return Values
The function returns the number of successfully matched and assigned input fields. This number can be zero if the function encounters
invalid input characters, as specified by the conversion specification, before it can assign input characters.
If the input ends before the first conflict or conversion, returns EOF. These functions return EOF on end of input and a short count for
missing or invalid data items.
Environment
In POSIX mode, the E, F, and X formats are treated the same as the e, f, and x formats, respectively; otherwise, the upper-case formats
expect double, double, and long arguments, respectively.
See Alsointro(3int), setlocale(3), strtod(3), strtol(3), printf(3int), getc(3s), printf(3s), scanf(3s)
Guide to Developing International Software
scanf(3int)