How can you flush a write using a file descriptor?
I think what you are looking for may be int fsync(int fd); or int fdatasync(int fd); fsync will flush the file from kernel buffer to the disk. fdatasync will also do except for the meta data.
stdio
How can I capture STDOUT to a string?
A handy function for capturing stdout into a string… The following method is a handy general purpose tool to capture stdout and return it as a string. (I use this frequently in unit tests where I want to verify something printed to stdout.) Note especially the use of the ensure clause to restore $stdout (and … Read more
How to send output to stderr?
After Rust 1.19 As of Rust 1.19, you can use the eprint and eprintln macros: fn main() { eprintln!(“This is going to standard error!, {}”, “awesome”); } This was originally proposed in RFC 1896. Before Rust 1.19 You can see the implementation of println! to dive into exactly how it works, but it was a … Read more
Cannot open include file: ‘stdio.h’ – Visual Studio Community 2017 – C++ Error
I got same problem with a project porting from Visual Studio 2013 to Visual Studio 2017. Fix: change Properties → General → Windows SDK Version to 10
Code for printf function in C [duplicate]
Here’s the GNU version of printf… you can see it passing in stdout to vfprintf: __printf (const char *format, …) { va_list arg; int done; va_start (arg, format); done = vfprintf (stdout, format, arg); va_end (arg); return done; } See here. Here’s a link to vfprintf… all the formatting ‘magic’ happens here. The only thing … Read more
Rerouting stdin and stdout from C
Why use freopen()? The C89 specification has the answer in one of the endnotes for the section on <stdio.h>: 116. The primary use of the freopen function is to change the file associated with a standard text stream (stderr, stdin, or stdout), as those identifiers need not be modifiable lvalues to which the value returned … Read more
GCC fatal error: stdio.h: No such file or directory
macOS I had this problem too (encountered through Macports compilers). Previous versions of Xcode would let you install command line tools through xcode/Preferences, but xcode5 doesn’t give a command line tools option in the GUI, that so I assumed it was automatically included now. Try running this command: xcode-select –install If you see an error … Read more
stdlib and colored output in C
All modern terminal emulators use ANSI escape codes to show colours and other things. Don’t bother with libraries, the code is really simple. More info is here. Example in C: #include <stdio.h> #define ANSI_COLOR_RED “\x1b[31m” #define ANSI_COLOR_GREEN “\x1b[32m” #define ANSI_COLOR_YELLOW “\x1b[33m” #define ANSI_COLOR_BLUE “\x1b[34m” #define ANSI_COLOR_MAGENTA “\x1b[35m” #define ANSI_COLOR_CYAN “\x1b[36m” #define ANSI_COLOR_RESET “\x1b[0m” int main … Read more
‘printf’ vs. ‘cout’ in C++
I’m surprised that everyone in this question claims that std::cout is way better than printf, even if the question just asked for differences. Now, there is a difference – std::cout is C++, and printf is C (however, you can use it in C++, just like almost anything else from C). Now, I’ll be honest here; … Read more