I'm trying to set up precompiled headers in a large C++ project compiled with GCC 5.4.
There is a file "PrecompiledHeaders.h", which includes all the other relevant headers. I've added the compile flag -include PrecompiledHeaders.h, but when compiling, the header is not found:
cc1plus: fatal error: PrecompiledHeaders.h: No such file or directory
compilation terminated.
CMakeFiles/Project.dir/build.make:62: recipe for target 'CMakeFiles/Project.dir/NetworkGameState.cpp.o' failed
But I'm sure it exists, in the same directory as all other h and cpp files. What's more, manually adding #include "PrecompiledHeaders.h" to the top of "NetworkGameState.cpp" does not produce an error.
What could go wrong?
This is a CMake, out-of-source build, by the way.
It's likely an issue with the path. From the GCC 5.4 manual (emphasis mine):
-include file
Process file as if #include "file" appeared as the first line of the primary source file. However, the first directory searched for file is the preprocessor's working directory instead of the directory containing the main source file. If not found there, it is searched for in the remainder of the #include "..." search chain as normal.
You need to either supply the full (relative or absolute) path to the header as the argument of the -include flag, or add its parent directory to the search chain using e.g. -I or -iquote.
Related
Good day,
I have a file that I'm trying to compile and within it has an #include to a statically linked binary.
#!/bin/bash
g++ -Wall -std=c++17 Message.cpp ../textmagic-rest-cpp/lib/libtextmagic.a
I am getting the following error: fatal error: libtextmagic.h: No such file or directory
The relative path that I provided is correct under the assumption that the current working directory is the directory in which the script is called/ran. I might be linking the binary incorrectly and I've searched around the internet but the other posts/resources did not help me.
Note that the script is run in the same directory as Message.cpp.
g++ has the -I and -L flags that do that for you. Your flag will look like this: -I/ThePathToYourHeaders and -L/ThePathToYourLib. I don't know if g++ supports relative paths there but absolut paths are guaranteed to work there.
Also you probably need to add a linker flag. For your project it will be -ltextmagic. It is just the name of the .a file you want to link with, without the lib in front of the filename.
The #include directive needs to "read" the header file you give it as argument, and that is not included in the static library.
You can either include using a relative path to the source file or pass the location of the header file to the compiler using the -I argument.
I am trying to install the hep-mc library listed here: https://github.com/cschwan/hep-mc for use on compute using the instructions listed in the documentation here: https://github.com/cschwan/hep-mc#installation . To compile one of the example files, I typed this into the terminal:
g++ -L/usr/local/hep-mc/include vegas_mpi_ex.cpp -o vegas_mpi
but I get these error messages:
mpi_vegas_ex.cpp:1:22: error: hep/mc.hpp: No such file or directory
mpi_vegas_ex.cpp:2:26: error: hep/mc-mpi.hpp: No such file or directory
mpi_vegas_ex.cpp:8:17: error: mpi.h: No such file or directory
in the beginning of my code, the declarations are like this:
#include "hep/mc.hpp"
#include "hep/mc-mpi.hpp"
#include <mpi.h>
The tutorial states that I should point the compiler to the location of the "include" folder that contains all the .hpp files, which I have done. Do you guys have any idea as to what I'm doing wrong?
It should also be noted that the compiler cannot find the mpi.h directory even though I have loaded the openmpi module.
-L sets paths where the linker searches for libraries to link. The option you're looking for is -I, which sets the paths where the compiler searches for #included files.
g++ -L/usr/local/hep-mc/include vegas_mpi_ex.cpp -o vegas_mpi
Oops!
g++ -I/usr/local/hep-mc/include vegas_mpi_ex.cpp -o vegas_mpi
-L specifies the path to library files; -I specifies the path to includes.
This is confusing because in terms of project management and distribution, we consider "the library" to include both binaries and header files, as well as documentation and all sorts of goodies. But at a technical level that is not what "library" means.
#include<apis/api1/api.h>
throws No such file or directory
i even tried moving api.h and api.cc to the main project directory and using
#include<api.h>
does the same thing even though it is in the exact same directory that the other classes use
i tried adding /apis/api1 to the compiler search path
that just crashes the compiler can someone tell me what to type into the compilers compilation line
#include <api.h>
is the way you include a system header. (That is, the header for a library installed on your system.) It does not search in the directory of the source file or in directories specified in -I command line arguments.
#include "api.h"
is the way you include your own headers. (But it will also search library header locations if it doesn't find the header locally.)
I created a simple Flex file to read and return tokens from a file. I generated the scanner file using the command flex -c++ scanner.l. When trying to compile the generated lex.yy.cc file I am getting the error as:
Fatal error: FlexLexer.h: No such file or directory
The include folder of flex contains the FlexLexer.h file. I also tried by copying the file to the same folder where lex.yy.cc resides. Still the error exists.
I am using Windows7.
How can I solve this problem. Thank You
The generated scanner uses the line:
#include <FlexLexer.h>
which means that the FlexLexer.h file will be searched for in system include directories. If you correctly install flex, the installation should put the FlexLexer.h file in some system include directory. If you just download the flex source and compile it without installing it, that won't work. And it might not work in the Windows environment either; I've never tried.
If you have no other alternative, and you're using gcc, you can tell gcc to use the include directory in the flex source tree as a system include directory using the command-line option -isystem /path/to/flex/include. There's almost certainly a VS2010 equivalent but I have no idea what it is.
Hi i would like to include a external library call NTL. its in the path as followed:
#include "WinNTL-5_4_2/include/NTL/tools.h"
My file is key.cpp and its reside in the same folder as NTL . but when i compile, it came up with another error which is ..
In file included from keygen.cpp:6:0:
WinNTL-5_4_2/include/NTL/tools.h:5:24: fatal error: NTL/ctools.h: No such file or directory
compilation terminated.
As its need another file call ctools.h, how do i includes tools.h to make ctools.h work also
I tried type
me#ubuntu:~/GG$ g++ keygen.cpp -o keygen -l WinNTL-5_4_2/include/
keygen.cpp:6:23: fatal error: NTL/tools.h: No such file or directory
but it doesnt work still.
Based on the error message, you should try changing your include to:
#include "NTL/tools.h"
and make sure that WinNTL-5_4_2/include is in your compiler's search path for include files.
You need to add the root directory as part of your project's search path for include files. It depends on your environment exactly how to do this, but there are usually two search paths -- one for include files and another for compiled libraries. Set that with the directory that contains the WinNTL-5_4_2 directory and you should be golden.
You had to add "fullpath/WinNTL-5_4_2/include" in you include path of your compiler (either by -I for gcc or in the include path list of a visual studio project)
Expecting that ctools.h exists in ".../WinNTL-5_4_2/include/NTL"