cannot open output file a.out: Permission denied, on a simple compilation
I wrote some code in vim and whenever I try to run the code it shows this:coolmego@coolmego-PC:~/coolmego/cprograms$ gcc dfs8puzz.c /usr/bin/ld: cannot open output file a.out: Permission denied...
View ArticleEmbed revision number in executable binary
I want to embed a git revision marker in my binary, but the linker appears to strip it away.Makefile:CPPFLAGS += -DREV=$(shell git describe) file.c:#define xstr(s) str(s) #define str(s) #s const char...
View ArticleHow do I use bcrypt in c++ under Linux using wrapper libbcrypt
I try to write a simple login script using bcrypt. I've tried to use the C wrapper libbcrypt library - https://github.com/trusch/libbcrypt - but got stucked with the compiler complaining about...
View Articlegcc FORTIFY_SOURCE drastically increases binary size
We have a very large C++ codebase that we would like to compile using gcc with the "FORTIFY_SOURCE=2" option to improve security and reduce the risk of buffer overflows. The problem is when we compile...
View ArticleCreate stub library/object from application code (ROM) using binutils for...
I have some C code that is implemented in a ROM. I'd like to link an application against that code, so I can save some space (as my application won't have to include the ROM code as it's already in the...
View ArticleStatically linking libc into my binary causes it to segfault
I need to build a binary with libc statically linked. I have libc.a available in the same directory as the source code. To compile, I tried the following: gcc -o foo foo.c libc.a This resulted in the...
View Articlegcc vs clang common library issue
I have two applications, one compiled with gcc(c++) and another compiled with clang++. I am to use common shared boost library for both the applications. My question is whether to compile boost shared...
View Articlehow do I remove `GLIBC_2.27' requirement at compile time?
I've been using a docker image for c++ compilation. It's based on Ubuntu 18.04. When I attempt to run on some Ubuntu 16 systems, I get this message:/lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.27'...
View ArticleWhat is the difference between g++ and gcc?
What is the difference between g++ and gcc? Which one of them should be used for general c++ development?
View ArticleMemory leak during unordered_map::insert KeyEqual exception with GCC -...
I'm using GCC 7.3.1, but also tested on coliru, which I believe is version 9.2.0. Build with the following:g++ -fsanitize=address -fno-omit-frame-pointer rai.cpp Here's rai.cpp:#include...
View ArticleCan GCC ignore nonexisting directories?
I have two projects: mylib and myproj mylib compiles into a shared object. myproj uses mylib. I linking myproj using:g++ -L../../mylib/Release myproj.o -lmylib That works fine on my development...
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C Program behaves differently if compiled using CLion rather than using gcc...
I'm writing a program to play 4 in a row using C90.I made a UI for the Console using ASCII characters.If I compile the program using C Lion I get the following output:If I compile it using gcc main.c...
View ArticlePortable equivalent to gcc's __attribute__(cleanup)
Recently I came across a gcc extension that I have found rather useful: __attribute__(cleanup)Basically, this allows you to assign a cleanup call to a local variable at the time it exits scope. For...
View ArticleRound double to nearest non subnormal representation
In C++ there are (sometimes) subnormal doubles that are finite, not nan and not zero.How can I round them to nearest non subnormal double representation?For example: std::isnormal(DBL_MIN/2.0) = false
View ArticleHow C preprocessor works?
How does the C Preprocessor handle multiple macros? I searched it over here and Google too but not able to understand the exact rule that should be followed. The following code:#define ABC xYz #define...
View ArticleGCC 7, -Wimplicit-fallthrough warnings, and portable way to clear them?
We are catching warnings from GCC 7 for implicit fall through in a switch statement. Previously, we cleared them under Clang (that's the reason for the comment seen below):g++ -DNDEBUG -g2 -O3...
View ArticleHow can I compile a text file into a C++ program as a const string?
I have a C++ program which I'd like to have output a certain text file at some point. Of course I could have it open, read, and output the text file, but then I have to keep the binary and the text...
View ArticleRecursive call in static function - gcc produces recursive_init_error exception
We have some code that has been recently ported to Linux (gcc 7.1 - glibc 2.17). I've included some snippets below - we use these macros in our class headers like shown below. This is all fine on...
View ArticleEnable to compile sdl 1.2 project on macbook
I try this : g++ -Wall affichage.c -o game -D_REENTRANT -I/usr/local/Cellar/sdl/1.2.15_1/SDL but I have this error : Undefined symbols for architecture x86_64: "_SDL_EnableKeyRepeat", referenced from:...
View ArticleC++ function`s declaration and definition are different but it works well
I'm writing some C++ code And I found a very strange thing Like below code, it works well even though a function's declaration and definition are different Does anyone know how can this is possible?...
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