Never-completed type error when creating structure of function pointers in C

Question

I'm trying to create a structure which contains multiple function pointers, however when I try to create an instance of the structure I get a error "variable "stCmdTable" was declared with a never-completed type".

I have a header file in which I have the following code:

typedef int (*pStCmd) (void);

struct stCmdStruc {
  pStCmd id;
  pStCmd measure;
  pStCmd setRelay;
};

typedef struct stCmdStruct stCmdStruct;

stCmdStruct stCmdTable;

I want to create stCmdTable and assign functions to all the function pointers in the stCmdTable, but when it doesn't like my declaration of stCmdTable.

I've also tried doing something like this, where I try to initialise all the function pointers to functions straight of the bat with my structure defintion, but it really doesn't like this telling me expected a ";" at the end of each line in the struct.

typedef int (*pStCmd) (void);

struct stCmdStruc {
  pStCmd id = sendId2;
  pStCmd measure = sendMeasurement2;
  pStCmd setRelay = setRelay2;
};

typedef struct stCmdStruct stCmdStruct;

stCmdStruct stCmdTable;

Can anyone please shed some light on what I'm doing wrong?

Please edit your question to include a Minimal, Complete, and Verifiable Example. And then also include a copy-paste (as text) of the full and complete error output from the example, including any possible informational notes. — Some programmer dude
– Some programmer dude, Commented Oct 30, 2018 at 11:11
Please ask only one question in the question. Your second question is separate issue and should be asked separately. — user694733
– user694733, Commented Oct 30, 2018 at 11:13
C++ automatically introduces the structure name as a type name; C does not. Either use struct before stCmdStruct or add typedef struct stCmdStruct stCmdStruct;. — Jonathan Leffler
– Jonathan Leffler, Commented Oct 30, 2018 at 11:22
“C++ ...” yah, that modicum of convenience is like the free hit of heroin; what could go wrong if you try just a bit more.... — mevets
– mevets, Commented Oct 30, 2018 at 12:24

Jim Fell · Accepted Answer · 2018-10-30 15:00:14Z

1

Try this . . .

typedef int (*pStCmd_Type) (void);

typedef struct _stCmdStruct {
  pStCmd_Type id;
  pStCmd_Type measure;
  pStCmd_Type setRelay;
} stCmdStruct_Type;

stCmdStruct_Type stCmdTable[your_table_size];

stCmdTable[0].id = sendId2;
stCmdTable[0].measure = sendMeasurement2;
stCmdTable[0].setRelay = setRelay2;

answered Oct 30, 2018 at 15:00

Jim Fell

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