Sponsored Content
Full Discussion: C header file and extern
Top Forums Programming C header file and extern Post 302851821 by Corona688 on Monday 9th of September 2013 06:02:02 PM
Old 09-09-2013
You got it exactly backwards.

You should put this in the header file:

Code:
extern const char ack_msg[];


...and this in one and only one C file, call it "data.c" perhaps:

Code:
#include "data.h"

const char ack_msg[] = "ack: received your msg\n";

The string can be used in any C file which does #include "data.h"
This User Gave Thanks to Corona688 For This Post:
 

10 More Discussions You Might Find Interesting

1. Programming

extern for functions

Hi, Please let me know if the extern keyword is necessary for using functions which is defined and declared in another file and and used in a different file where both these files are linked together. thanks (8 Replies)
Discussion started by: naan
8 Replies

2. Linux

Reading the header of a tar file(posix header)

say i have these many file in a directory named exam. 1)/exam/newfolder/link.txt. 2)/exam/newfolder1/ and i create a tar say exam.tar well the problem is, when i read the tar file i dont find any metadata about the directories,as you cannot create a tar containig empty directories. on the... (2 Replies)
Discussion started by: Tanvirk
2 Replies

3. Programming

Extern variable.

file1.c int a1; int main() { a1 = 2; printf("\na1 = %d\n", a1); next(); printf("\na1 = %d\n", a1); next1(); printf("\na1 = %d\n", a1); } file2.c #include <stdio.h> int b1 = 0; void next(void) (1 Reply)
Discussion started by: Tanvirk
1 Replies

4. Linux

Problem mounting extern hd (fedora 9)

Hi there, I'm having a bit of a strange problem which I would appreciate some help with. The Problem: I have two external hard drives, but I'm borrowing one off my parents to copy data too (one of mine, which is identical to theirs - WD MyBook 300g - is on its way out). Fedora 9 recognizes... (3 Replies)
Discussion started by: lasthidingplace
3 Replies

5. UNIX for Dummies Questions & Answers

fetchmail and forward to an extern address

Hi, I'm searching for an solution for the following problem. I want fetch some mails via pop3 from a@a.com with fetchmail. That works perfectly. Now any incoming mail should forwarded to b@b.com via smtp obv. But I don't know how to configure that. All online tutorials describe forwarding to... (0 Replies)
Discussion started by: mcW
0 Replies

6. Programming

segmentation fault for extern

Why this is happening when both of them compiled together and run? I am getting segmentation fault SIGSEGV. File1.c: int arr; File2.c: extern int *arr; int main() { arr = 100; } (3 Replies)
Discussion started by: royalibrahim
3 Replies

7. Shell Programming and Scripting

Comparing one file header with another file header

Hi Experts, In our project we have requirement where in we have to compare header of one file with header in the parameter file. There are 20 files which we ftp from one site. All this files have different header. We are comapring this file with our parameter file(which is having the header... (2 Replies)
Discussion started by: Amey Joshi
2 Replies

8. UNIX for Dummies Questions & Answers

Merge all csv files in one folder considering only 1 header row and ignoring header of all others

Friends, I need help with the following in UNIX. Merge all csv files in one folder considering only 1 header row and ignoring header of all other files. FYI - All files are in same format and contains same headers. Thank you (4 Replies)
Discussion started by: Shiny_Roy
4 Replies

9. Programming

Extern keyward on function in C

I saw a header (.h) file with mixture of "regular" function declarations and other extern function declarations. As I was told all function declarations are implicitly external and the extern on functions declarations is superfluous. Here my focus is on function declaration, not variable yet. int... (2 Replies)
Discussion started by: yifangt
2 Replies

10. Shell Programming and Scripting

Find header in a text file and prepend it to all lines until another header is found

I've been struggling with this one for quite a while and cannot seem to find a solution for this find/replace scenario. Perhaps I'm getting rusty. I have a file that contains a number of metrics (exactly 3 fields per line) from a few appliances that are collected in parallel. To identify the... (3 Replies)
Discussion started by: verdepollo
3 Replies
ppmtosixel(1)                                                 General Commands Manual                                                ppmtosixel(1)

NAME
ppmtosixel - convert a portable pixmap into DEC sixel format SYNOPSIS
ppmtosixel [-raw] [-margin] [ppmfile] DESCRIPTION
Reads a portable pixmap as input. Produces sixel commands (SIX) as output. The output is formatted for color printing, e.g. for a DEC LJ250 color inkjet printer. If RGB values from the PPM file do not have maxval=100, the RGB values are rescaled. A printer control header and a color assignment table begin the SIX file. Image data is written in a compressed format by default. A printer control footer ends the image file. OPTIONS
-raw If specified, each pixel will be explicitly described in the image file. If -raw is not specified, output will default to com- pressed format in which identical adjacent pixels are replaced by "repeat pixel" commands. A raw file is often an order of magni- tude larger than a compressed file and prints much slower. -margin If -margin is not specified, the image will be start at the left margin (of the window, paper, or whatever). If -margin is speci- fied, a 1.5 inch left margin will offset the image. PRINTING
Generally, sixel files must reach the printer unfiltered. Use the lpr -x option or cat filename > /dev/tty0?. BUGS
Upon rescaling, truncation of the least significant bits of RGB values may result in poor color conversion. If the original PPM maxval was greater than 100, rescaling also reduces the image depth. While the actual RGB values from the ppm file are more or less retained, the color palette of the LJ250 may not match the colors on your screen. This seems to be a printer limitation. SEE ALSO
ppm(5) AUTHOR
Copyright (C) 1991 by Rick Vinci. 26 April 1991 ppmtosixel(1)
All times are GMT -4. The time now is 02:01 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy