On Tue, 31 Jul 2007 04:27:13 -0700, nisa wrote:
> hi,
> i am quite new to programming using system calls and would like a basic
> idea regarding the usage of system calls.
> i would like assistance in the following area of c programming in linux:
> 1.how to open a text file ,read data and print the data on console using
> system calls
> 2.create a text file and write some data 3.read data from a file and
> append that data to another file using lseek() 4.creation of a parent
> and child process using fork()
Well, just to not let you in blank, here is a VERY simple file that reads
a text file, and output it to the screen
#include <stdio.h> //standard IO
#include <stdlib.h> //for reading files
#include <string.h> //for memset
#include <errno.h> //for errno
int main(int argc, char *argv[]){
FILE *fp = NULL;
char ch[1];
if(argc!=2){
fprintf(stderr,"Usage:%s <file>\n",argv[0]);
return 1;
}
memset(ch,'\0',sizeof(char)*1);
if((fp=fopen(argv[1],"r"))==NULL){
perror("fopen");
return errno;
}
while(feof(fp)==0){
if( (fread(ch,sizeof(char),1,fp)==0) && (feof(fp)==0) ){
perror("fread");
fclose(fp);
memset(ch,'\0',sizeof(char)*1);
return errno;
}
fprintf(stdout,"%c",ch[0]);
}
fclose(fp);
memset(ch,'\0',sizeof(char)*1);
return 0;
}
Also, as it was stated before, use the man pages. If you don't have a
Linux box, then google will be your friend for this.
In this example, you would need, the man pages for fopen(),fread() and
feof().
Good luck.
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