Sponsored Content
Full Discussion: Function open() sets errno
Top Forums Programming Function open() sets errno Post 302826993 by DGPickett on Thursday 27th of June 2013 05:10:58 PM
Old 06-27-2013
Well open() returns an integer, which if -1 means errno is set to tell you what you did wrong. It sounds like your access in not good. You can set errno to zero before and test afterward. The nature of errno is that it is only set for errors, not reset on success. I usually:
Code:
if ( 0 > ( fd = open( file_name_ptr, O_RDONLY ))){
    perror( file_name_ptr );
    exit( 1 );
  }

This User Gave Thanks to DGPickett For This Post:
 

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

function to test if file is open

I need to write a function that will work in sh/ksh shell that will test to see if a file has already been opened for writting by another user has anyone written something like this? (3 Replies)
Discussion started by: johnsonbryce
3 Replies

2. Virtualization and Cloud Computing

Clouds (Partially Order Sets) - Streams (Linearly Ordered Sets) - Part 2

timbass Sat, 28 Jul 2007 10:07:53 +0000 Originally posted in Yahoo! CEP-Interest Here is my follow-up note on posets (partially ordered sets) and tosets (totally or linearly ordered sets) as background set theory for event processing, and in particular CEP and ESP. In my last note, we... (0 Replies)
Discussion started by: Linux Bot
0 Replies

3. UNIX and Linux Applications

(lmgrd) Can't open /usr/tmp/.flexlm/lmgrdl.4081, errno: 24

We are a tool vendor and one of our users is getting this error. The user is using several macrovision(FLEXLM) license enabled products including ours. (lmgrd) Can't open /usr/tmp/.flexlm/lmgrdl.4081, errno: 24 At this time, it stops checking out licenses, and will not respond to query's.... (2 Replies)
Discussion started by: return_user
2 Replies

4. Programming

errno

Hey, Can I assume that for certain function calls, errno can never be set to a certain value. More specifically, can I assume that for if the stat function call fails, the errno can never be or "No space left on device." I am assuming that a read function cannot fail because of no space... (5 Replies)
Discussion started by: the_learner
5 Replies

5. UNIX and Linux Applications

Sybase help: Open client, bcp function

To begin: I use Linux The Problem: I need bcp functionality for scripts. Perl modules, such as Sybase:xfer, require ctlib which comes with Sybase Open Client. Talking with Sybase sales reps is an exercise in futility and hate. They know absolutely nothing about their own products and will... (0 Replies)
Discussion started by: Bubnoff
0 Replies

6. Programming

Open function of sys/stat.h

If a process already has the entire file locked for read and write using newstruct.l_type = F_WRLCK; what would happen if another process would try to open it in read only mode using open(filename, O_RDONLY); ? I want to check if the file exists and I want it to work even if another process has... (4 Replies)
Discussion started by: cyler
4 Replies

7. Shell Programming and Scripting

Help !! perl open function

Help Please perl Gurus, I am trying to add ungrouped passengers in a group and I creating a script however it fails on first step only I tried all the options it returns following error. syntax error at junki line 4, near "open " Execution of junki aborted due to compilation errors. ... (2 Replies)
Discussion started by: dynamax
2 Replies

8. Shell Programming and Scripting

Open file function

Hello all, just a quick little part of code i'm writing to check if the file i'm writing too in my automatic process is not being written too manually. #!/bin/bash FUSER=$(/sbin/fuser -s /toto.tmp >/dev/null 2>&1) LSOF=$(/usr/sbin/lsof | grep -q "toto.tmp") PGREP=$(pgrep -f "toto.tmp" >... (6 Replies)
Discussion started by: maverick72
6 Replies

9. HP-UX

Failed to open tape device /dev/rmt/0mn:Device busy (errno = 16)

Hi, Unable to make tape backup, please help. /opt/ignite/bin/make_tape_recovery -a /dev/rmt/?mn -I -v -m tar -x inc_entire=vg00 * Creating local directories for configuration files and archive. ======= 04/25/16 16:28:08 IST Started /opt/ignite/bin/make_tape_recovery. (Mon... (4 Replies)
Discussion started by: anuragr
4 Replies
perror(3C)						   Standard C Library Functions 						perror(3C)

NAME
perror, errno - print system error messages SYNOPSIS
#include <stdio.h> void perror(const char *s) #include <errno.h> int errno; DESCRIPTION
The perror() function produces a message on the standard error output (file descriptor 2) describing the last error encountered during a call to a system or library function. The argument string s is printed, followed by a colon and a blank, followed by the message and a NEW- LINE character. If s is a null pointer or points to a null string, the colon is not printed. The argument string should include the name of the program that incurred the error. The error number is taken from the external variable errno, which is set when errors occur but not cleared when non-erroneous calls are made. See Intro(2). In the case of multithreaded applications, the -mt option must be specified on the command line at compilation time (see threads(5)). When the -mt option is specified, errno becomes a macro that enables each thread to have its own errno. This errno macro can be used on either side of the assignment as though it were a variable. USAGE
Messages printed from this function are in the native language specified by the LC_MESSAGES locale category. See setlocale(3C). ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
Intro(2), fmtmsg(3C), gettext(3C), setlocale(3C), strerror(3C), attributes(5), standards(5), threads(5) SunOS 5.11 12 Jul 2007 perror(3C)
All times are GMT -4. The time now is 11:40 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy