In the C programming language, it is my understanding that variables can only be defined at the beginning of a code block, and the variable will have the scope of the block it was declared in. With that in mind, I was wondering whether it is considered bad practice to artificially create a new scope as in this example: void foo() { ...
Is there a wait statement in c-component? for example, wait for 0.5 second before continuing the process? thanks! ...
I have a typedef int my_type and i have a function which looks like void my_func (my_type* x); How should I use this func to modify x using the best practice? ...
What is the behavior of the select(2) function when a file descriptor it is watching for reading is closed by another thread? From some cursory testing, it does return right away. I suspect the outcome is either that (a) it still continues to wait for data, but if you actually tried to read from it you'd get EBADF (possibly -- there's ...
Hi, We have a quite large (280 binaries) software project under Linux and currently it has a very dispersed code structure - that means one can't [work out] what code from the source tree is valid (builds to deployable binaries) and what is deprecated. But the Makefiles are good. We need to calculate C/C++ SLOC for entire project. Here...
I'm doing a small project in C after quite a long time away from it. These happen to include some file handling. I noticed in various documentation that there are functions which return FILE * handles and others which return (small integer) descriptors. Both sets of functions offer the same basic services I need so it really does not mat...
I want to read sizeof(int) bytes from a char* array. a)In what scenario's we need to worry if endian needs to be checked b)how would you read the first 4 bytes considering taking endian consideration or no consideration. EDIT: The sizeof(int) bytes that I have read needs to be compared with the an integer value. What is the best app...
sscanf(input_str, "%5s", buf); //reads at max 5 characters from input_str to buf But I need to use something like %MACRO_SIZEs instead of %5s A trivial solution is to create a format string for the same char fmt_str[100] = ""; snprintf(fmt_str, 100, "%%%ds", MACRO_SIZE); sscanf(input_str, fmt_str, buf); Is there a better way to...
I'm trying to extract specific hard coded variables from C source code. My remaining problem is that I'd like to parse array initialisation, for example: #define SOMEVAR { {T_X, {1, 2}}, {T_Y, {3, 4}} } It's enough to parse this example into "{T_X, {1, 2}}" and "{T_Y, {3, 4}}", since it's then possible to recurse to get the full struc...
Hi all, Chapter 6 Language of the C Standard defines all the different concepts, conversions, lexical elements, expressions, declarations, statements, blocks, external definitions and so on which are defined in the C standard. I was wondering if there is a reference body of code anywhere which contains all these elements of the C langu...
My question is a slight variation on the question What is the best way to test whether a file exists on Windows?, with some specific caveats. Specifically, the data is located on a mapped drive, and the SMB 2.0 protocol is used. (By definition, this requires that the drive be mapped from a Vista machine to either a Vista or Server 2008...
I am debugging some Linux C code in a signal handler for floating point exceptions. The goal is to check the floating point registers, print some information, and then abort. I get a segmentation fault when attempting to printf the result of (char)('0' + phyreg). struct ucontext * uc = (struct ucontext *) data; fpregset_t fp = uc ...
Given the following code: void foo( int* array ) { // ... } void bar( int** matrix ) { // ... } int main( void ) { int array[ 10 ]; int matrix[ 10 ][ 10 ]; foo( array ); bar( matrix ); return 0; } I don't understand why I get this warning: warning: passing argument 1 of ‘bar’ from incompatible poi...
Is it possible to do something like this #ifdef SOMETHING #define foo // #else #define foo MyFunction #endif The idea is that if SOMETHING is defined, then calls to foo(...) become comments (or something that doesn't get evaluated or compiled), otherwise it becomes a call to MyFunction. I've seen __noop used, but I don't believe I ca...
For some reason, my installation of gcc seems to be printing an "a with a carat" character in place of all %s's in its error messages, e.g., test.c:4: error: expected â, â, â, â or â before â token Has anyone else seen this before? (Needless to say, it's difficult to Google for.) (This is on Ubuntu 8.10) Edit: The guy at http://ubun...
I came across this line in some code and can't find the syntax defined anywhere: *(float *)csCoord.nX = lImportHeight* .04f; /* magic number to scale font size */ If I remove the f from .04f then the compiler gives a warning about possible data loss due to a conversion from 'double' to 'float'. I assume the f is doing some sort...
After opening a pipe to a process with popen, is there a way to kill the thread that is started? Using pclose is not what I want because that will wait for the thread to finish, but I need to kill it. ...
Can someone provide an example were casting a pointer from one type to another fails due to mis-alignment? In the comments to this answer, bothie states that doing something like char * foo = ...; int bar = *(int *)foo; might lead to errors even on x86 if alignment-checking is enabled. I tried to produce an error condition after set...
I'm trying to write some code that reads a file and ignores the line breaks (\n), so far I have: c = fgetc(fp); for(int loop = 0; c != EOF; loop++) { if((c != '\n') && (c != '\\')) { buffer[loop] = c; } c = fgetc(fp); } but its just not seeming to ignore the '\n' bits (not sure about the '\') And sorry for the la...
I am working with Apple's ScriptingBridge framework, and have generated a header file for iTunes that contains several enums like this: typedef enum { iTunesESrcLibrary = 'kLib', iTunesESrcIPod = 'kPod', iTunesESrcAudioCD = 'kACD', iTunesESrcMP3CD = 'kMCD', iTunesESrcDevice = 'kDev', iTunesESrcRadioTuner = 'kTun'...