if(aptr[i] < bptr[i])
a->used = BI_LESS_THAN;
else
return BI_GREATER_THAN;
I can not figure out why this code will not compile. It says that it is expecting a '}' before the start of the else. Is this invalid in C? I am compiling in Netbeans using GCC.
The error is consistent with your BI_LESS_THAN macro being malformed. Before the file is actually compiled, the C preprocessor will substitute BI_LESS_THAN with whatever you have defined it to, exactly as it's written. That's why the compiler error seems a little cryptic.
Related
I'm writing a simple code in C language, and this works.
Which compiles and excutes with no errors, gives the expected output.
#include <stdio.h>
int main(void) {
struct SiteTemplate {
int views;
};
int visit(struct SiteTemplate *site) {
site -> views++;
return 0;
}
struct SiteTemplate site;
site.views = 0;
visit(&site);
printf("%d\n", site.views);
return 0;
}
But in my VS Code, with C_Cpp linting is on, my IDE shows the following error and other problems with it.
declaration is incompatible with previous "visit" (declared at line 8)
Having a screenshot of it:
This error linting is really confusing me since my code works with gcc, it doesn't show any error when compiling.
And also, if I move my struct and function definition to the global level instead of inside main(), then the errors don't exist anymore... But what's the error declaration is incompatible? Or is there any problem with my code?
Click here to view the another screenshot to save whitespaces of this page.
By the way, the version of my VS Code is 1.52.0, with default C_Cpp linting.
Nested function definition is not standard C, it's supported by compiler extensions. According to C standard, any function definition needs to appear outside of any other function definition.
Hi I have been trying to port LWIP to a new arm device. When compiling the code i get the error message:
"lwip/lwip-1.4.0/src/include/lwip/memp_std.h:35:23: error: expected ')' before numeric constant"
When I go to this file this and below this several similar macros is what I find on that line:
LWIP_MEMPOOL(RAW_PCB, MEMP_NUM_RAW_PCB, sizeof(struct raw_pcb), "RAW_PCB")
If I remove the need for this macro with a define to deactivate the RAW functionality the error moves to the next LWIP_MEMPOL() macro.
The define it seems to want to put a ')' in front of is defined as this:
#define MEMP_NUM_RAW_PCB 1
The RAW_PCB is not defined but is "combined with MEMP_" to create an element in an enum.
I have tried to complie the whole ting with the -E option to get human redable object files and see if i can find any open '(' around the areas where MEMP_RAW_PCB apears and the substitution of MEMP_NUM_RAW_PCB to 1 but I have not found any by manual inspection yet.
Are there any suggestions on what can be going on here or what more I can do or look for to find the cause of the error?
I should maybe add that so far I don't call on any of the LWIP code from main() or any of the functions used in main().
I solved it with:
#ifndef MEMP_STD_H_
#define MEMP_STD_H_
... // memp_std.h codes ...
#endif //#ifndef MEMP_STD_H_
The error suggests you have unbalanced parentheses. The code you have provided thus far does not indicate where this problem is, but since ) is expected, it probably means the error is actually in the lines of code preceding the one you have shown.
Examine the code preceding the line you have shown (perhaps after using gcc -E) to check to see if all the parentheses are balanced.
If you're defining it with the dash-D option, it will generate the 1 by default, e.g.:
gcc -D 'MAX(A,B) ((A) < (B)? (B) : (A))' ...
Generates:
#define MAX(A,B) ((A) < (B)? (B) : (A)) 1
And you get the error: expected ‘)’ before numeric constant message at the line where the substitution occurs because of that trailing 1, e.g.:
int maxval = MAX(i,j);
// generates: int maxval = ((i) < (j)? (j) : (i)) 1;
Conversely, if you use the assignment operator to explicitly define the value, it will generate it the way you expected. E.g.:
int maxval = MAX(i,j);
// generates: int maxval = ((i) < (j)? (j) : (i));
I am using Microsoft Visual Studio 2010 to write a C code. This is the piece of code that I defined :
#define setImagVal_Matrix(matrix,type,x,y,val) \
(getImagVal_Matrix(matrix,type,x,y) = (val))
Then I am using it inside this function :
for(bands=0; bands < no_of_bands; bands++) {
outputmatrix[bands] = new_Matrix(yrange,xrange,getDataType_Image(inputImage),getDataFormat_Image(inputImage));
for(r=0; r < no_of_rows; r++) {
for(c=0; c < no_of_cols; c++) {
if(c<x1 || c>x2 || r<y1 || r>y2)
{
continue;
}
else
{
setImagVal_Matrix(outputmatrix[bands],getDataType_Matrix(outputmatrix[bands]),c-x1,r-y1,123);
}
}
}
}
However, it shows me this error on setImagVal_Matrix function call:
"Error:expected an expression"
And when I build the solution , here is the output which shows a syntax error on the same line:
1>c:\cviplab-net-2010\cviplab\crop.c(50): error C2059: syntax error : ')'
After spending couple of hours, I still cannot find the cause of the error . Any idea how to fix it?
EDIT:
I analyzed the pre-processed file and found the syntax error but still I don't know how to fix it. Here is the line which makes the error :
((((((outputmatrix[bands])->data_type) **)((outputmatrix[bands])->iptr))[r-y1][c-x1]) = (123));
the error is for the ) after **
Just stop using macros as functions. Try this:
inline void setImagVal_Matrix(int matrix, int type, int x, int y, int val) {
getImagVal_Matrix(matrix, type, x, y) = val;
}
Change the int types as appropriate, and you'll get the compiler helping you with useful error messages instead of cryptic ones. Heck, it'll even help you figure out the argument types.
Within your macro, you do an assignment to something that does not look like an lvalue. Do you mean ==?
I would like to propose at least to use brackets for the macro arguments:
#define setImagVal_Matrix((matrix),(type),(x),(y),(val)) \
(getImagVal_Matrix((matrix),(type),(x),(y)) = (val))
Also, to see if it is really bracket issue, you can try to look at preprocessed file.
But, actually using macro for this purpose is not a good one practice. If you care about function call you can make the function inline:
inline void setImagVal_Matrix(matrix,type,x,y,val) {
getImagVal_Matrix(matrix,type,x,y) = val;
}
In spite of the fact that inline is only recommendation for the compiler, this will allow to avoid a lot of compilation errors and hardly debugging run-time errors.
Since yesterday, I've been facing a compiling error for my C project. The project itself consists on creating a service that will make some tasks.
I don't what has changed since yesterday, but this morning, my code can't compile anymore.
Here are the errors I have :
c:\path\main.c(56): error C2275: 'SERVICE_TABLE_ENTRY' : illegal use of this type as an expression
c:\program files\microsoft sdks\windows\v7.0a\include\winsvc.h(773) : see declaration of 'SERVICE_TABLE_ENTRY'
c:\path\main.c(56): error C2146: syntax error : missing ';' before identifier 'DispatchTable'
c:\path\main.c(56): error C2065: 'DispatchTable' : undeclared identifier
c:\path\main.c(56): error C2059: syntax error : ']'
c:\path\main.c(57): error C2065: 'DispatchTable' : undeclared identifier
c:\path\main.c(57): warning C4047: 'function' : 'const SERVICE_TABLE_ENTRYA *' differs in levels of indirection from 'int'
c:\path\main.c(57): warning C4024: 'StartServiceCtrlDispatcherA' : different types for formal and actual parameter 1
Here's the code concerned by these errors (from lines 45 to 58) :
int main(int ac, char *av[])
{
if (ac > 1)
{
if (!parse_args(ac, av))
{
aff_error(ARGUMENTS);
return EXIT_FAILURE;
}
}
SERVICE_TABLE_ENTRY DispatchTable[] = {{MY_SERVICE_NAME, ServiceMain}, {NULL, NULL}};
StartServiceCtrlDispatcher(DispatchTable);
return EXIT_SUCCESS;
}
And here's the code of my ServiceMain function :
void WINAPI ServiceMain(DWORD ac, LPTSTR *av)
{
gl_ServiceStatus.dwServiceType = SERVICE_WIN32;
gl_ServiceStatus.dwCurrentState = SERVICE_START_PENDING;
gl_ServiceStatus.dwControlsAccepted = SERVICE_ACCEPT_STOP;
gl_ServiceStatus.dwWin32ExitCode = 0;
gl_ServiceStatus.dwServiceSpecificExitCode = 0;
gl_ServiceStatus.dwCheckPoint = 0;
gl_ServiceStatus.dwWaitHint = 0;
gl_ServiceStatusHandle = RegisterServiceCtrlHandler(MY_SERVICE_NAME, ServiceCtrlHandler);
if (gl_ServiceStatusHandle == (SERVICE_STATUS_HANDLE)0)
return;
gl_ServiceStatus.dwCurrentState = SERVICE_RUNNING;
gl_ServiceStatus.dwCheckPoint = 0;
gl_ServiceStatus.dwWaitHint = 0;
SetServiceStatus(gl_ServiceStatusHandle, &gl_ServiceStatus);
}
I couldn't manage to find some answers that fit my problem, could anyone helps ? Thanks !
When you name your source files *.c, MSVC assumes it's compiling C, which means C89. All block-local variables need to be declared at the beginning of the block.
Workarounds include:
declaring/initializing all local variables at the beginning of a code block (directly after an opening brace {)
rename the source files to *.cpp or equivalent and compile as C++.
upgrading to VS 2013, which relaxes this restriction.
You might be using a version of C that doesn't allow variables to be declared in the middle of a block. C used to require that variables be declared at the top of a block, after the opening { and before executable statements.
Put braces around the code where the variable is used.
In your case that means:
if (ac > 1)
{
if (!parse_args(ac, av))
{
aff_error(ARGUMENTS);
return EXIT_FAILURE;
}
}
{
SERVICE_TABLE_ENTRY DispatchTable[] = {{MY_SERVICE_NAME, ServiceMain}, {NULL, NULL}};
StartServiceCtrlDispatcher(DispatchTable);
}
This error occurred when transferring a project from one installation to another (VS2015 => VS2010).
The C code was actually compiled as C++ on the original machine, on the target machine the "Default" setting in Project Properties\C/C++\Advanced\Compile as was somehow pointing to C even though the source file was of type *.cpp.
In my small program, errors popped up regarding the placement in code of certain types e.g. HWND and HRESULT as well as on the different format of for loops , and C++ constructs like LPCTSTR, size_t, StringCbPrintf and BOOL. Comparison.
Changing the "Compile as" from Default to Compile as C++ Code (/TP) resolved it.
This will also give you "illegal use of this type as an expression".
WRONG:
MyClass::MyClass()
{
*MyClass _self = this;
}
CORRECT:
MyClass::MyClass()
{
MyClass* _self = this;
}
You might be wonder the point of that code. By explicitly casting to the type I thought it was, when the compiler threw an error, I realized I was ignoring some hungarian notation in front of the class name when trying to send "this"
to the constructor for another object. When bug hunting, best to test all of your assumptions.
My current job at the university is to port a C program from MinGW (windows) to Visual Studio (nmake).
I have got a valid "makefile.vc" file for a very similar C program.
My approach was to adopt the Makefile (i.e. "makefile.vc") to the program I need to port.
All but four C files seem to compile fine. Those four files have various errors for example, syntax errors and "unknown size".
Should I continue with my approach to change the Makefile or use CMAKE instead of nmake?
Is there a tutorial or any other pointer on porting a C program from MinGW/gcc to nmake?
typedef struct {
A_TypeConverter *converter;
char *domain;
} enumeratorConverterEntry;
static enumeratorConverterEntry enumeratorConverterEntries[]; /* line 186 */
error:
f.c(186) : error C2133: 'enumeratorConverterEntries' : unknown size
typedef struct AsmInstructionInfo {
int flags;
CONST char **argTypes; /* line 7 */
int minArgs;
int maxArgs;
int cArgs;
} AsmInstructionInfo;
error:
fAssemble.c(7) : error C2061: syntax error : identifier 'CONST'
..
/* file fStack.c: */
#ifdef CHECK_ACTIVATION_COUNTS
/* code */
#endif
/* more code */
void fShowStack(l_Interp *interp) { /* line 94 */
l_CallFrame *framePtr;
/* more code */
error:
fStack.c(94) : error C2143: syntax error : missing ')' before '*'
fStack.c(94) : error C2143: syntax error : missing '{' before '*'
fStack.c(94) : error C2059: syntax error : ')'
fStack.c(94) : error C2054: expected '(' to follow 'interp'
static enumeratorConverterEntry enumeratorConverterEntries[]; /* line 186 */
That looks like a valid incomplete, forward declaration of an array, which would be valid syntax, except I think for the static qualifier. I don't have a copy of the 'C' standard in front of me, but reading between the lines on the results of Googling "forward declaration of static array" seems to indicate that an incomplete definition of a static array results in undefined behavior, so Microsoft and GNU are legitimately entitled to do whatever they want with it. GNU accepts it, and Microsoft rejects it. As Mark Wilkins points out you should be make the Microsoft compiler happy by replacing it with:
extern enumeratorConverterEntry enumeratorConverterEntries[]; /* line 186 */
In general it's worth noting that the Microsoft compiler only supports the C89 standard, while the GNU compiler supports portions of the C99 standard, and several of their own extensions, depending on the arguments to the compiler.
The errors in fAssemble.c and fStack.c look like one or more preprocessor files are missing or incomplete. You should search your source to find out where CONST and l_Interp are defined, and then figure out why they are not being picked up in the files where the errors are occurring.
I just now tried out that array declaration with MinGW, and it does compile. To make it link, though, it needs the array to be defined elsewhere. The result is that it appears to be the same as the extern storage class:
extern enumeratorConverterEntry enumeratorConverterEntries[];
I'm not sure if there are other subtleties associated with the original declaration using a static storage class for the global.