This is the header file and its C file:
cs50.h and
cs50.c
Now I use them in the following example http://www.paste.ubuntu.com/576370/ — which is no longer available.
I already put the header file in /usr/bin/include or something like that and when I try to compile my code using gcc -o xxx xxx.c, it doesn't work, so tried to fix this and the following way worked: http://www.paste.ubuntu.com/576371/ — which is no longer available.
Now I want to do something to make the 'make' command work as the gcc does.
What do I need to do?
The following was the old topic:
I was using gcc command to
compile C programs but after a period
of time I got a problem. I need
to compile a new header file and use
it as a library.
The header file called cs50.h.
so after doing it and it's ok I can
compile using the following
gcc -o xxx xxx.c -lcs50
It works but now I want to use 'make'
command and I can't get it to work.
It just don't compile the header file
and library as gcc was before I edit
it to accept the cs50 library.
So now I want to add to the 'make'
command the following: -lcs50
Can anyone help me in this please?
Near the top of your Makefile, add the line:
LDLIBS = -lcs50
If you are using Make's default (implicit) rules for the building, then that is all you need to do. If you are using explicit rules, you will need to add $(LDLIBS) to your explicit rules.
If there is no Makefile, then make is using default rules, and you can either just create a makefile with
echo LDLIBS = -lcs50 > Makefile
or tell make to link with certain libraries by specifying the required libraries in LDLIBS in the environment. For example, if you are using a sh-derived shell (anything other than csh or tcsh) you can do:
LDLIBS=-lcs50 make target
If you are using a csh variant, you can do:
env LDLIBS=-lcs50 make target
or just do (again, for non-csh shells)
export LDLIBS=-lcs50
before running make. (For csh variants, do setenv LDLIBS -lcs50)
You can use below “make” command to link library and include header directories,
make <.c or .cpp source filename_without_extension> LDLIBS="-l<lib1> -l<lib2>"
suppose you have server.cpp file to compile using make command,
make server LDLIBS="-lcpprest -lpthread -lssl -lcrypto" LDFLAGS="-L/usr/lib/" CXXFLAGS="-I/usr/include/"
Output will expand the compilation command as,
g++ -I/usr/include/ -L/usr/lib/ server.cpp -lcpprest -lpthread -lssl -lcrypto -o server
Did you forget that you have to tell gcc in what directory the CS50 library is located?
gcc … -L/directory/for/cs50_library -lcs50
Related
I am doing the CS50 class, I have installed the cs50.h.
Based on the instructions I used the following command in terminal to compile my simple program and just want to make sure I understand everything im asking terminal to do.
Line is:
gcc -g hello.c -o hello -lcs50 -lm
I know the following*: gcc =
gcc = gnu compiler for C
-g = generate source-level debug information
Hello.c = name of the file we want to compile
-o = write output file
hello = our output file name
Can anyone tell me what -lcs50 and -lm are? My guess is that its calling on the library lcs50 in (-lcs50) but again this is a guess and would like to know for sure.
Everything works as it should with no issues
Thanks,
Mostly correct.
-o is not required to generate the output file, it's only needed to customize the name. (-o and the following name can only appear together).
-lcs50 means "link the library called cs50", not lcs50. It will try to find this file using several different name patterns, e.g. libcs50.so (on Linux), [lib]cs50.dll[.a] (on Windows), libcs50.a (on both), something else on Mac.
-lm links the standard math library, but I don't think you need to manually specify it on most modern GCC distributions.
Yes. For -lm, it's for the maths library, which is not linked by default. This is explained well at Why do you need an explicit `-lm` compiler option.
I found a useful library on github for my project, after building this later I tried to use some predefined function on it. I couldn't compile my project because there is some header file missing like this one :
In file included from main.c:2:0:
ptask.h:11:19: fatal error: ptime.h: No such file or directory
I compiled my project using this command :
gcc main.c -L. -lptask
This is all the files in project folder :
libptask.a main.c ptask.h
This is the library content:
$ ar -t libptask.a
pbarrier.c.o
pmutex.c.o
ptask.c.o
ptime.c.o
rtmode.c.o
tstat.c.o
libdl.c.o
dle_timer.c.o
calibrate.c.o
Do I need to add all the headers of this files or just link the lib when compiling ?
Your main.c #include-s ptask.h which in turn #include-s ptime.h. Having compiled static libs alone is not enough (that's the linker's job), you still need to have all used header files (which is the compiler's job), both the ones you use and their dependencies, recursively applicable.
Normally you need to be sure that the header files are in your "include path", something that a lot of compilers define with -I as a command-line option. You'll need to include the source directory of that library, or if it has a make install option, then the place where they got installed.
regarding:
gcc main.c -L. -lptask
this is performing the compile step and the link step in one command.
It is also not enabling the warnings, which should always be enabled during the compile step.
Suggest something similar to the following to compile
gcc -Wall -Wextra -Wconversion -pedantic -std=gnu11 -g -c main.c -o main.o -I.
and when you have fixed all the warnings, then use something similar to the following to link
gcc main.o -o main -L. -lptask
I'm trying to compile my C code but I need to tell the GCC compiler where two file are.
The two files are located here
/usr/local/ssl/include/
/usr/local/ssl/lib/
I want to add this to my gcc -o file file.c so that my program can work.
In gcc, the -I option is used for adding a directory to the set of directories to search for header files, and the -L option is used for adding a directory to the set of directories to search for libraries. Since you're not explicitly linking in any libraries, you shouldn't need the -L option in this case.
gcc -I/usr/local/ssl/include -o file file.c
If you were linking in libraries, something like the following format should work, assuming that file.c calls a function in libmyLib.a:
gcc -I/usr/local/ssl/include -o file file.c -L/path/to/my/library -lmyLib
See this question for more details regarding library linking order.
Sorry. I think this question would be very easy to you guys.
I have two c files and one h file, I put those two .c files stack.c and main.c and one .h file stack.h inside a folder named "test" at Desktop.
So they are in C:\Users\user\Desktop\test
However when i try to test this code by writing
gcc -c stack.c sq_main.c -l stack.h
It continuously shows "unkown type name ..."
I think the header file is not included into those two .c files.
Actually I wrote the code
#include "stack.h"
Inside stack.c and main.c
Can anyone tell me how to include header file properly?
You are using GCC wrongly. I guess you are on Linux (or on something emulating it like MinGW ...)
If you insist on giving several commands in a terminal, you'll need to run
gcc -Wall -Wextra -g -c stack.c
gcc -Wall -Wextra -g -c sq_main.c
these two commands are building object files stack.o & sq_main.o (from stack.c & the #include-d stack.h, and sq_main.c & the #include-d stack.h, respectively). The options -Wall -Wextra are asking for all warnings and some extra warnings. The -g option asks for debugging information. The -c option asks for compiling only. Assuming that they are enough for your program, you need to link these object files to make an executable:
gcc -g stack.o sq_main.o -o myprogram
You might need to add -Iinclude-directory options to the compiling commands (the first two), and you might need to add -Llibrary-directory and -llibrary-name to the linking command. Order of arguments to gcc matters a lot. You could also add -H to ask the compiler to show which files are included. And GCC has a lot of other options. Read the Invoking GCC chapter of its documentation.
The .o suffix might be .obj on most Windows systems. You might also need myprogram.exe instead of myprogram. I never used Windows so I cannot help more.
In practice, you should use GNU make and write some Makefile; this answer might inspire you.
I am trying to compile a C program which uses regexes on FreeBSD. I have checked in /usr/local/include and the file pcre.h is definitely there.
However, no matter what I do, I get the following compiler error:
/usr/home/myname/project/include/pcre_wrap.h:4:18: error: pcre.h: No such file or directory
What could be going wrong? My understanding of C libraries on Unix could be better...
As the comment above says you need to use #include. If this isn't working you may want to export an environment variable C_INCLUDE_PATH that points to the header file.
Failing that why not try adding -I/usr/local/include to your gcc call, something like gcc myfile.c -I/usr/local/include -o myexe