Compilation Error of C code on Linux (Same code compiles on OSX)

Question

I am trying to compile some code on linux that I KNOW compiles on OSX, but I am getting some issues.

All of the files have headers named .h, and all of the files are in the same directory. I am compiling like this:

gcc *.c -std=c99 -lpthread

And while this code does compile on OSX, I get a bunch of weird linker errors on my Ubuntu install. Am I missing a few compiler options? It is a default Ubuntu-server install with the additional packages gcc and build-essential installed.

In file included from errorLogger.h:24:0,
                 from configParser.h:17,
                 from configParser.c:9:
signalHandling.h:24:18: error: unknown type name ‘sigset_t’
configParser.c: In function ‘parseConfigFile’:
configParser.c:114:5: warning: implicit declaration of function ‘getline’ [-Wimplicit-function-declaration]
In file included from errorLogger.h:24:0,
                 from global.h:18,
                 from connection.h:19,
                 from connection.c:10:
signalHandling.h:24:18: error: unknown type name ‘sigset_t’
connection.c: In function ‘createConnectionQueue’:
connection.c:189:28: warning: assignment makes integer from pointer without a cast [enabled by default]
In file included from errorLogger.h:24:0,
                 from database.h:16,
                 from database.c:9:
signalHandling.h:24:18: error: unknown type name ‘sigset_t’
In file included from errorLogger.h:24:0,
                 from errorLogger.c:10:
signalHandling.h:24:18: error: unknown type name ‘sigset_t’
errorLogger.c: In function ‘reportError’:
errorLogger.c:63:5: warning: implicit declaration of function ‘strerror_r’ [-Wimplicit-function-declaration]
errorLogger.c: In function ‘logMessage’:
errorLogger.c:87:5: warning: implicit declaration of function ‘localtime_r’ [-Wimplicit-function-declaration]
errorLogger.c: In function ‘processErrorQueue’:
errorLogger.c:131:17: warning: implicit declaration of function ‘open’ [-Wimplicit-function-declaration]
errorLogger.c:131:57: error: ‘O_APPEND’ undeclared (first use in this function)
errorLogger.c:131:57: note: each undeclared identifier is reported only once for each function it appears in
errorLogger.c:131:68: error: ‘O_CREAT’ undeclared (first use in this function)
errorLogger.c:131:78: error: ‘O_WRONLY’ undeclared (first use in this function)
errorLogger.c:131:88: error: ‘S_IWRITE’ undeclared (first use in this function)
errorLogger.c:131:99: error: ‘S_IREAD’ undeclared (first use in this function)
errorLogger.c:146:13: warning: implicit declaration of function ‘fsync’ [-Wimplicit-function-declaration]
errorLogger.c: In function ‘startErrorLogger’:
errorLogger.c:167:36: error: ‘O_APPEND’ undeclared (first use in this function)
errorLogger.c:167:47: error: ‘O_CREAT’ undeclared (first use in this function)
errorLogger.c:167:57: error: ‘O_WRONLY’ undeclared (first use in this function)
errorLogger.c:167:67: error: ‘S_IWRITE’ undeclared (first use in this function)
errorLogger.c:167:78: error: ‘S_IREAD’ undeclared (first use in this function)
errorLogger.c:214:57: error: ‘O_EXCL’ undeclared (first use in this function)
errorLogger.c:231:27: warning: assignment makes integer from pointer without a cast [enabled by default]
errorLogger.c: In function ‘closeErrorLogger’:
errorLogger.c:246:9: warning: implicit declaration of function ‘pthread_kill’ [-Wimplicit-function-declaration]
In file included from errorLogger.h:24:0,
                 from global.h:18,
                 from global.c:9:
signalHandling.h:24:18: error: unknown type name ‘sigset_t’
In file included from main.c:23:0:
signalHandling.h:24:18: error: unknown type name ‘sigset_t’
main.c: In function ‘main’:
main.c:53:5: warning: implicit declaration of function ‘blockSignals’ [-Wimplicit-function-declaration]
main.c:61:45: error: invalid application of ‘sizeof’ to incomplete type ‘struct addrinfo’ 
main.c:62:29: error: invalid application of ‘sizeof’ to incomplete type ‘struct addrinfo’ 
main.c:64:10: error: dereferencing pointer to incomplete type
main.c:65:10: error: dereferencing pointer to incomplete type
main.c:66:10: error: dereferencing pointer to incomplete type
main.c:66:23: error: ‘AI_PASSIVE’ undeclared (first use in this function)
main.c:66:23: note: each undeclared identifier is reported only once for each function it appears in
main.c:69:5: warning: implicit declaration of function ‘getaddrinfo’ [-Wimplicit-function-declaration]
main.c:73:9: warning: implicit declaration of function ‘gai_strerror’ [-Wimplicit-function-declaration]
main.c:73:9: warning: format ‘%s’ expects argument of type ‘char *’, but argument 4 has type ‘int’ [-Wformat]
main.c:73:9: warning: format ‘%s’ expects argument of type ‘char *’, but argument 4 has type ‘int’ [-Wformat]
main.c:81:41: error: dereferencing pointer to incomplete type
main.c:83:30: error: dereferencing pointer to incomplete type
main.c:83:46: error: dereferencing pointer to incomplete type
main.c:83:64: error: dereferencing pointer to incomplete type
main.c:96:30: error: dereferencing pointer to incomplete type
main.c:96:44: error: dereferencing pointer to incomplete type
main.c:112:5: warning: implicit declaration of function ‘freeaddrinfo’ [-Wimplicit-function-declaration]
main.c:138:9: error: unknown type name ‘fd_set’
main.c:142:9: warning: implicit declaration of function ‘FD_ZERO’ [-Wimplicit-function-declaration]
main.c:143:9: warning: implicit declaration of function ‘FD_SET’ [-Wimplicit-function-declaration]
main.c:145:9: warning: implicit declaration of function ‘pselect’ [-Wimplicit-function-declaration]
In file included from signalHandling.c:10:0:
signalHandling.h:24:18: error: unknown type name ‘sigset_t’
signalHandling.c:12:18: error: unknown type name ‘sigset_t’
signalHandling.c: In function ‘setHandler’:
signalHandling.c:51:53: error: invalid application of ‘sizeof’ to incomplete type ‘struct sigaction’ 
signalHandling.c:52:36: error: invalid application of ‘sizeof’ to incomplete type ‘struct sigaction’ 
signalHandling.c:54:5: warning: implicit declaration of function ‘sigemptyset’ [-Wimplicit-function-declaration]
signalHandling.c:54:30: error: dereferencing pointer to incomplete type
signalHandling.c:60:9: warning: implicit declaration of function ‘sigaddset’ [-Wimplicit-function-declaration]
signalHandling.c:60:35: error: dereferencing pointer to incomplete type
signalHandling.c:67:17: error: dereferencing pointer to incomplete type
signalHandling.c:72:9: warning: implicit declaration of function ‘sigaction’ [-Wimplicit-function-declaration]

Solution 1

I'm assuming that the immediate objective is to get the code to compile at all, and that once that's done, you'll go back and revise the source so it works out of the box on both platforms. That means that hacks are acceptable very short-term; they'll be fixed properly as you gain knowledge about what the portability issues are. (If it's any consolation, the first alternative system to the one where the software was originally developed is usually the hardest; after that, it generally gets easier.)

The first thing to try is:

gcc *.c -std=gnu99 -lpthread

This tells system header files to define many more symbols than -std=c99. (There's some dissent on this topic, which is OK. At the least, if you add -pedantic to a -std=c99 compilation, then symbols in standard C headers defined by POSIX are not exposed unless you also request POSIX support — see below. Since you don't have -pedantic, that may not be a factor in the compilations, in which case quietly move on to the next recommendation, which is the basis for future portability to POSIX systems.)

If that is insufficient to get you back on track, then you'll probably need to use something like:

gcc *.c -std=gnu99 -D_XOPEN_SOURCE=700 -lpthread

This says "Provide me with the POSIX and X/Open functions corresponding to POSIX 2008". You can try 600 and 500 for older versions, but you probably won't need to do so on Linux. In due course, you're likely to set _XOPEN_SOURCE automatically, either through a configuration header or via a configuration tool. While you're getting things to compile at all, specifying it on the command line is OK. In due course, you'll be using a makefile or equivalent to control the compilation and not typing a gcc command line at the shell.)

The sigset_t is defined in <signal.h> under POSIX. So, requesting POSIX support explicitly should get things to compile again properly. If you still get types such as sigset_t undeclared, then there must be a header on Mac OS X that includes the standard headers such as <signal.h> but which does some unrelated task on Linux (and therefore does not include <signal.h>). That will require source code scrutiny. However, it is relatively unlikely to be necessary.

Solution 2

You need to include additional header files because different system headers include other different system headers.

Also for example gcc has been working hard to not included headers that it should not.

Is signalHandling.h including #include <signal.h> where sigset_t is defined?

EDIT

After talking with the OP it seems the problems was a compile/link problem. Compiling the source into object files first and then linking them after seemed to have solved their problem.

Comments

[Admin]

The only difference between -std=c99 and -std=gnu99 is whether the compiler will accept certain GCC language extensions. It does not affect the contents of header files.

[Norman Ramsey]

It's nice to know about <signal.h>, but solving a portability problem by adding -std=gnu99? I'm not so happy...

[Jonathan Leffler]

@NormanRamsey: there's a short-term 'get it compiled' and 'any hack will do' operation, which is what I'm addressing. Then there's the engineered solution which makes the hackery unnecessary, because the code works correctly on both systems automatically or almost automatically (whether because of autoconf or conservative assumptions or ...). Any option such as -std=c99 is inherently specific to GCC; it doesn't apply to other compilers in general.

[Jonathan Leffler]

In case of desparation, use (1) gcc with the -H option (as well as any others you're using) to list where the headers are installed, and (2) cd /usr/include; grep -r -e sigset_t -l . (assuming that most of the headers are in /usr/include). This will tell you whether sigset_t is defined somewhere on your Linux box. If not, you need some extra package installed. If it is, then you have to work out how to get it defined. You can repeat the grep exercise for any other missing symbol.

[charliehorse55]

That grep command returns a few files, including signal.h when run in /usr/include/. Running gcc with -H shows that that is where it is including signal.h from.

[charliehorse55]

signalHandling.h does include signal.h

[Adrian Cornish]

Have you looked in signal.h grep -w sigset_t * signal.h:50:typedef __sigset_t sigset_t;

[charliehorse55]

Yes, that line is present in signal.h

[Adrian Cornish]

Is it there if you try compiling configParser.c with -E passed to gcc - you may need to pipe the output somewhere and look for it.

[charliehorse55]

Good idea, I think I may be close to the root of the problem. If I just compile one of my files, I get the error (among others): connection.c:(.text+0x18a): undefined reference to 'sem_wait'. However running -E on gcc and then passing it to grep sem_wait shows this: extern int sem_wait (sem_t *__sem); sem_wait(parallelThreads);

[Adrian Cornish]

It may also trying to compile each file into a binary (ie link it) you really should add -c to create and object file and then link all the object files into a executable at the end. The error you show is a linker error not a compiler error

[Adrian Cornish]

By the way - passing -E to gcc makes it just preprocess the files - it does not compile them. This can help debugging if there are macro expansion issues/#define issues. Basically this is showing the code gcc will try and compile for you

[charliehorse55]

let us continue this discussion in chat

[Norman Ramsey]

@JonathanLeffler yes it's that short-term mindset that gives me the collywobbles :)

[tommyo]

I got compilation errors on signal related system calls when compiling with -std=c99. -D_XOPEN_SOURCE=700 solved it.