see if i write in any c file like
#include "header.h"
then it will search this file in current directory
but when i write
#include <header.h>
then where it will go to find this file ?
what is defualt path for header file included in c program?
see i have installed gstreamer in /usr/local but when i am including
#include <gst/gst.h>
i am geeting fatal error: gst/gst.h: No such file or directory
How can i remove this error?
Try running gcc -v -E -. When I do, part of the output is as follows:
#include <...> search starts here:
/usr/lib/gcc/i686-linux-gnu/4.6.1/include
/usr/local/include
/usr/lib/gcc/i686-linux-gnu/4.6.1/include-fixed
/usr/include/i386-linux-gnu
/usr/include
It's not an answer to the gstreamer question, but I hope this still helps!
Pulled from here
The default paths are
/usr/local/include
/usr/include
If you use another path, you can add in your compile command with -I flag. In your case, assuming you have a /usr/local/gst/include directory, you may add -I/usr/local/gst/include and use #include <whatever_you_need.h>
The path searched depends on the implementation (and current configuration). The correct way to find the include path is to use pkg-config
pkg-config --cflags gstreamer
The default path for <> stuff is /usr/include, at least on Unix.
You can add as many default paths as you want with -I /my/new/path compiler option.
`gcc -print-prog-name=cc1` --verbose
and then CTRL+C
you can find those files in:
/usr/include
Related
Compiling C with gcc.
While
#include "/absolute/path/to/my/file"
works OK,
#include "../../relative/path/to/my/file"
fails with "no such file or directory". This only happens when the file is placed outside the project directory. file has read permissions. What could be the reason?
When using the format
#include "some_file.h"
the preprocessor by default looks in the same directory as the source file, if the file is not found there, it looks in the header-file search paths.
If the header file is not in the same directory as the source file, and not in one of the directories of the preprocessors search-path, then it will not be found.
You can write relative or full paths though:
#include "../some_directory/some_file.h"
Yes, you need GCC Options for Directory Search
When using gcc and local header files you need to add an include path to your build command.
mysource.c:
#include "localfile.h"
build command:
gcc -o program mysource.c
This works as long as the header file is in the same directory as your source (where you're running the command). If your header file is in a different directory you can include with the -I option:
gcc -I../headerdir -o hello.exe hello.c
or an absoulte path:
gcc -I/home/user/myprogra/headerdir -o hello.exe hello.c
I installed on windows curl 7.28.0 from curl-7.28.1-devel-mingw32.zip through minGW console to default directory like:
./config && make && make install
All needed headers (aka curl.h, types.h ...) I see in C:\MinGW\msys\1.0\local\include\curl
libcurl.pc placed in C:\MinGW\msys\1.0\local\lib\pkgconfig\
libcurl.a, libcurl.dll.a and libcurl.la placed in C:\MinGW\msys\1.0\local\lib.
My download_file.c file includes are:
...
#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>
...
I try to compile the C code with followed command through gcc:
$ gcc -IC:/MinGW/msys/1.0/include/
-IC:/MinGW/msys/1.0/local/include/curl
-IC:/MinGW/msys/1.0/local/lib/pkgconfig
-o download_file download_file.c -llibcurl -lcurl
with absolute path get the same error:
gcc -I/include/
-I/local/include/curl
-I/local/lib/pkgconfig
-o download_file download_file.c -llibcurl -lcurl
But I still get an error:
download_file.c:21:23: fatal error: curl/curl.h: No such file or directory compilation terminated.
row 21 is #include <curl/curl.h>
What I did wrong? Please help.
You have the curl/ directory in the source code, but also in the option.
It seems the option should point out the higher-level directory in which curl/ is, so it should be something like:
-I/local/include/
I think the problem is likely that you give your include paths on the command line in the Win32 path format. This is not the same as the one used by msys (or ultimately Cygwin).
Try these:
$ gcc -I/include/
-I/local/include/curl
-I/local/lib/pkgconfig
...
Hope I got the absolut paths right, but you can check in your msys shell.
What ticked me off was that you use ./config, which wouldn't work from the Command Prompt, but works from the msys shell. So you need to give paths that all the programs in MinGW understand.
Basically, most programs in MinGW only have the concept of a single file system root, like on any unixoid system, while Win32 has multiple (the drive letters). Since the MinGW programs are linked accordingly, you need to give paths that they understand.
Thank you very much to #0xC0000022L and #unwind. By your help I fixed my problem.
0xC0000022L you are right about absolute path
unwind you are right about -I/local/include/ instead -I/local/include/curl
I found other problem: -L/local/lib instead -I/local/lib.
So this is a working command:
gcc -I/include/
-I/local/include
-L/local/lib
-o download_file download_file.c -llibcurl -lcurl
I'm using cygwin and trying to set up Winpcap. I have the following sample directory structure:
/a/basic_dump.c
/a/pcap.h
/usr/include/pcap/pcap.h
The basic_dump.c file has #include "pcap.h" (which it finds). The /a/pcap.h file has #include <pcap/pcap.h>.
Withing the /a directory, I execute gcc -c basic_dump.c. However, I get pcap/pcap.h: no such file or directory.
I've also tried using -I /usr/include/pcap and -I /usr/include but no luck.
Any help is appreciated.
Thanks
Try the following:
gcc basic_dump.c -o basic_dump -I/usr/include/pcap -I/usr/include
This tutorial explains how to write and compile C programs with libpcap which can be a good reference for you.
Try removing the space between -I and the path to your includes.
I am trying to compile a small .c file that has the following includes:
#include <openssl/ssl.h>
#include <openssl/rsa.h>
#include <openssl/x509.h>
#include <openssl/evp.h>
In the same folder where I have the .c file I have a /openssl with all those files (and more), also in synaptic package manager I see OpenSSL installed, I am trying to compile with this:
gcc -o Opentest Opentest.c -lcrypto
but I always get the errors:
error: openssl/ssl.h: No such file or directory
error: openssl/rsa.h: No such file or directory
error: openssl/x509.h: No such file or directory
error: openssl/evp.h: No such file or directory
The file I want to compile is only a .c file, doesn't have Makefile or ./configure.
I already tried:
env CFLAGS=-I/path/to/openssl/
and tried to compile again but I get the same errors.
What should I do in order to compile with OpenSSL includes?
Your include paths indicate that you should be compiling against the system's OpenSSL installation. You shouldn't have the .h files in your package directory - it should be picking them up from /usr/include/openssl.
The plain OpenSSL package (libssl) doesn't include the .h files - you need to install the development package as well. This is named libssl-dev on Debian, Ubuntu and similar distributions, and openssl-devel on CentOS, Fedora, Red Hat and similar.
Use the -I flag to gcc properly.
gcc -I/path/to/openssl/ -o Opentest -lcrypto Opentest.c
The -I should point to the directory containing the openssl folder.
Use the snippet below as a solution for the cited challenge;
yum install openssl
yum install openssl-devel
Tested and proved effective on CentOS version 5.4 with keepalived version 1.2.7.
You need to include the library path (-L/usr/local/lib/)
gcc -o Opentest Opentest.c -L/usr/local/lib/ -lssl -lcrypto
It works for me.
If the OpenSSL headers are in the openssl sub-directory of the current directory, use:
gcc -I. -o Opentest Opentest.c -lcrypto
The pre-processor looks to create a name such as "./openssl/ssl.h" from the "." in the -I option and the name specified in angle brackets. If you had specified the names in double quotes (#include "openssl/ssl.h"), you might never have needed to ask the question; the compiler on Unix usually searches for headers enclosed in double quotes in the current directory automatically, but it does not do so for headers enclosed in angle brackets (#include <openssl/ssl.h>). It is implementation defined behaviour.
You don't say where the OpenSSL libraries are - you might need to add an appropriate option and argument to specify that, such as '-L /opt/openssl/lib'.
From the openssl.pc file
prefix=/usr
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include
Name: OpenSSL
Description: Secure Sockets Layer and cryptography libraries and tools
Version: 0.9.8g
Requires:
Libs: -L${libdir} -lssl -lcrypto
Libs.private: -ldl -Wl,-Bsymbolic-functions -lz
Cflags: -I${includedir}
You can note the Include directory path and the Libs path from this. Now your prefix for the include files is /home/username/Programming .
Hence your include file option should be -I//home/username/Programming.
(Yes i got it from the comments above)
This is just to remove logs regarding the headers. You may as well provide -L<Lib path> option for linking with the -lcrypto library.
For this gcc error, you should reference to to the gcc document about Search Path.
In short:
1) If you use angle brackets(<>) with #include, gcc will search header file firstly from system path such as /usr/local/include and /usr/include, etc.
2) The path specified by -Ldir command-line option, will be searched before the default directories.
3)If you use quotation("") with #include as #include "file", the directory containing the current file will be searched firstly.
so, the answer to your question is as following:
1) If you want to use header files in your source code folder, replace <> with "" in #include directive.
2) if you want to use -I command line option, add it to your compile command line.(if set CFLAGS in environment variables, It will not referenced automatically)
3) About package configuration(openssl.pc), I do not think it will be referenced without explicitly declared in build configuration.
My development environment is such that I have some_header.h in /usr/include and in /another/directory. /another/directory contains some header files I need to include in my program, but I want to use some_header.h from /usr/include. When I use
gcc ... -I/another/directory
gcc uses /another/directory/some_header.h. If I use
gcc ... -I/usr/include -I/another/directory
gcc does the same thing because it ignores /usr/include since it is part of the standard search path, but it gets searched after non standard directories included with -I.
Any ideas?
Use the -iquote switch:
Include the files that are in another/directory using quotes:
#include "another_file.h"
Then use
gcc -iquote /another/include ...
to add a search path for quoted include files. This switch will add a directory that is searched for quoted include files after the current directory and before -I and system include paths.
Include your other include files using brackets (i.e. #include <header.h>).
See here for more information:
Where are include files stored - Ubuntu Linux, GCC
Have you looked at -nostdinc ?
The manual says:
-nostdinc
Do not search the standard system directories for header files.
Only the directories you have specified with -I options (and the
directory of the current file, if appropriate) are searched.
Of course that means that you will have to specify anything that normally goes on the standard search path that you do want...
Have you tried unsetting the system INCLUDE path environment variable?