11.6.1.2080 READ-FILE FILE

( c-addr u₁ fileid -- u₂ ior )

Read u₁ consecutive characters to c-addr from the current position of the file identified by fileid.

If u₁ characters are read without an exception, ior is zero and u₂ is equal to u₁.

If the end of the file is reached before u₁ characters are read, ior is zero and u₂ is the number of characters actually read.

If the operation is initiated when the value returned by FILE-POSITION is equal to the value returned by FILE-SIZE for the file identified by fileid, ior is zero and u₂ is zero.

If an exception occurs, ior is the implementation-defined I/O result code, and u₂ is the number of characters transferred to c-addr without an exception.

An ambiguous condition exists if the operation is initiated when the value returned by FILE-POSITION is greater than the value returned by FILE-SIZE for the file identified by fileid, or if the requested operation attempts to read portions of the file not written.

At the conclusion of the operation, FILE-POSITION returns the next file position after the last character read.

A.11.6.1.2080 READ-FILE.

A typical sequential file-processing algorithm might look like: In this example, THROW is used to handle exception conditions, which are reported as non-zero values of the ior return value from READ-FILE. End-of-file is reported as a zero value of the "length" return value.