What GNU C extensions are available that aren't trivial to implement in C99?
How come the Linux kernel can compile only with GCC? What GNU C extensions are really necessary for some projects and why? ...
c
Problem with pointers and getstring function
I am trying to write a function to get a string from uart. Its for an embedded system so I don't want to use malloc. The pointer that is passed to the getstring function seems to point to garbage after the gets_e_uart1() is called. I don't use pointers too often so I'm sure it is something really stupid and trivial that Im doing wrong. ...
How do find the longest path in a cyclic Graph between two nodes?
Hi, I already solved most the questions posted here, all but the longest path one. I've read the Wikipedia article about longest paths and it seems any easy problem if the graph was acyclic, which mine is not. How do I solve the problem then? Brute force, by checking all possible paths? How do I even begin to do that? I know it's goin...
Capistrano update causes C: to be placed in the current directory (cygwin)
When I run cap deploy:update in a directory on my local machine (via cygwin), "C:" magically appears in the directory. Sure enough, I can cd to it and it's my windows C: drive. Now I'm afraid to delete it, but I definitely don't want it in this directory (a rails project under /home/username/blah/blah). Here's my config/deploy.rb file. ...
Include headers in header file?
I have several libraries made by myself (a geometry library, a linked list library, etc). I want to make a header file to include them all in one lib.h. Could I do something like this: #ifndef LIB_H_ #define LIB_H_ #include <stdio.h> #include <stdlib.h> #include <linkedlist.h> #include <geometry.h> .... #endif Then I could just refe...
Eclipse CDT -- How to map Linux path's to Windows paths?
We have a C-code project written for a Linux environment but we also want the ability to view and edit the code on Eclipse for Windows and have the headers be resolved. The problem we are facing is that a lot of the headers are included with absolute paths in the Linux format such as: #include "/path/to/custom/header.h" What I would l...
multiple valgrind errors: Conditional jump or move depends on uninitialised value(s)
I'm running valgrind and I'm getting the following error (this is not the only one): ==21743== Conditional jump or move depends on uninitialised value(s) ==21743== at 0x4A06509: index (mc_replace_strmem.c:164) ==21743== by 0x33B7CBB3CD: gaih_inet (in /lib64/libc-2.5.so) ==21743== by 0x33B7CBD629: getaddrinfo (in /lib64/libc-2.5...
realloc()ing memory for a buffer used in recv()
I need to recv() data from a socket and store it into a buffer, but I need to make sure get all of the data so I have things in a loop. So to makes sure I don't run out of room in my buffer, I'm trying to use realloc to resize the memory allocated to the buffer. So far I have: // receive response int i = 0; int amntRecvd = 0; char *...
Assigning values to chars in structs - c
I have been having trouble getting my head around allowing a user to enter words into structs. The struct I am using is below struct class { char class_num[4]; char *class_name; } If anyone could point me how to do this or at least point me in the right direction that wuld be great. thanks ...
C programming fopen
#include <stdio.h> #include <stdlib.h> typedef struct aluno{ char cabecalho[60]; char info[100]; int n_alunos; char dados[100]; char curso[100]; int numero; char nome[100]; char e_mail[100]; ...
Implementing a Mutex Lock in C
I'm trying to make a really simple spinlock mutex in C and for some reason I'm getting cases where two threads are getting the lock at the same time, which shouldn't be possible. It's running on a multiprocessor system which may be why there's a problem. Any ideas why it's not working? void mutexLock(mutex_t *mutexlock, pid_t owner) { i...
Is it bad practice to use multi-dimensional arrays in C/C++?
Some programmers seem to violently hate them, while others seem to think they're fine. I know that anything that can be done to a multi-dimensional array can also be done to a regular array, so they're functionally equivalent. Is it bad practice to use multi-dimensional arrays, or does it not matter? ...
Use of enums in C?
Hi all, Is there anyway by which we can copy one enum to another one?For eg: enum Element4_Range{a4=1,b4,c4,d4}; enum Element3_Range{a3=1,b3,c3}; enum Element3_Range Myarr3[10]; enum Element4_Range Myarr4[10]; enum Element3_Range MyFunc(Element4_Range); main() { MyFunc(Myarr4); ...
Redirect stdin in C program to another process
I have a C program, and I'd like to have it filter all its input with tr. So, I'd like to start up tr as a child process, redirect my stdin to it, then capture tr's stdout and read from that. Edit: here's the code I have so far, which doesn't work. It segfaults instantly, but I don't understand why: #include <stdlib.h> #include <stdio....
Allocating memory for a char pointer that is part of a struct
hi, im trying to read in a word from a user, then dynamically allocate memory for the word and store it in a struct array that contains a char *. i keep getting a implicit declaration of function âstrlenâ so i know im going wrong somewhere. struct unit { char class_code[4]; char *name; }; char buffer[101]; struct unit units[1000...
Help with Strings in C
Given the char * variables name1 , name2 , and name3 , write a fragment of code that assigns the largest value to the variable max (assume all three have already been declared and have been assigned values). I've tried and came up with this: if ((strcmp(name1,name2)>0)&&(strcmp(name1,name3)>0)){ max=name1; } else if ((strcmp(...
path settup method
When we set the path on source code sometimes we use "\\" or "\"and sometimes we use "/".. What's the environment dependency between them? ...
How to resolve two structures with the same name?
In my code base I find that two modules have structures with the same name. It is giving a name conflict error. Is there a way to resolve it without changing the code? ...
memcpy(), what should the value of the size parameter be?
Hi, I want to copy an int array to another int array. They use the same define for length so they'll always be of the same length. What are the pros/cons of the following two alternatives of the size parameter to memcpy()? memcpy(dst, src, ARRAY_LENGTH*sizeof(int)); or memcpy(dst, src, sizeof(dst)); Will the second option always ...
How to deprecate a macro in GCC?
Hi, i Know how to use attribute deprecated to deprcate a function like this: int old_fn () __attribute__ ((deprecated)); But how to deprecate a Macro like this: #define OLD_MACRO 1 Thank you in advance. Eric ...