VMS Help FORTRAN, Statements, READ *Conan The Librarian (sorry for the slow response - running on an old VAX) |
Transfers data from external or internal units to internal storage. The meanings of the symbolic abbreviations used to represent the parameters in the READ statement syntax are as follows: extu Is the logical unit or internal file optionally or prefaced by UNIT=. UNIT= is required if unit is intu not the first element in the clist. fmt Specifies whether formatting is to be used for data editing, and if it is, the format specification or an asterisk (*) to indicate list-directed formatting. The "fmt" is optionally prefaced by FMT=, if "fmt" is the second parameter in the clist and the first parameter is a logical or internal unit specifier without the optional keyword UNIT=. nml Is the namelist group specification for namelist I/O. Optionally prefaced by NML=. NML= is required if namelist is not the second I/O specifier. rec Is the cell number of a record to be accessed directly. Optionally prefaced by REC= or by an apostrophe ('). iostat Is the name of a variable to contain the completion status of the I/O operation. Optionally prefaced by IOSTAT=. err Is the label of a statement to which control is transferred in the event of an error. Optionally prefaced by ERR=. end Is the label of a statement to which control is transferred in the event of an end-of-file. Optionally prefaced by END=. iolist Are the names of the variables, arrays, array elements, or character substrings from which or to which data will be transferred. Optionally an implied-DO list. keyspec Specifies the key of field value of a record to be accessed. Optionally prefaced by KEY=, KEYEQ=, KEYGE=, KEYGT=, KEYNXT, KEYNXTNE, KEYLT, or KEYLE. keyid Specifies the key field index that is to be searched for the specified key field value. Optionally in- cluded with keyspec and optionally prefaced by KEYID=. The control-list parameters are "extu" (or "intu"), "fmt", "nml", "rec", "iostat", "err", "end", "keyspec", and "keyid". The I/O list parameter is "iolist".
1 - Sequential |
1.1 - Formatted
Translates the data from character to binary format as specified by format specifications. Statement formats: 1. READ(extu,fmt[,iostat][,err][,end])[iolist] Reads from a specified external unit. 2. READ f[,iolist] Reads from FOR$READ (normally, the terminal).
1.2 - List-directed
List-directed sequential READ statement formats: 1. READ(extu,*[,iostat][,err][,end])[iolist] Reads from a specified external unit. Translates the data from character to binary format according to the data types of the variables in the I/O list. 2. READ *[,iolist] Reads from FOR$READ (normally, the terminal). Translates the data from character to binary format according to the data types of the variables in the I/O list.
1.3 - Namelist
Namelist sequential READ statement formats: 1. READ(extu,nml[,iostat][,err][,end]) Reads from a specified external unit. Translates the data from character to binary format according to the data types of the list entities in the corresponding NAMELIST statement. 2. READ nl Reads from FOR$READ (normally, the terminal). Translates the data from character to binary format according to the data types of the entities in the corresponding NAMELIST statement.
1.4 - Unformatted
Unformatted sequential READ statement format: READ(extu,[,iostat][,err][,end])[iolist] Reads from a specified external unit. Does not translate the data.
2 - Direct |
2.1 - Formatted
Formatted direct READ statement format: READ(extu,fmt,rec[,err][,iostat])[iolist] READ(u'r,fmt[,err][,iostat]) [iolist] Reads from a specified external unit. Translates the data from character to binary format as specified by "fmt".
2.2 - Unformatted
Unformatted direct READ statement format: READ(extu,rec[,err][,iostat])[iolist] READ(u'r[,err][,iostat])[iolist] Reads from a specified external unit. Does not translate the data.
3 - Indexed |
3.1 - Formatted
Formatted Indexed READ statement format: READ(extu,fmt,keyspec[,keyid][,err][,iostat])[iolist] Reads from a specified external unit. Translates the data from character to binary format as specified by "fmt".
3.2 - Unformatted
Unformatted Indexed READ statement format: READ(extu,keyspec[,keyid][,err][,iostat])[iolist] Reads from a specified external unit. Does not translate the data.
4 - Internal |
Internal READ statement format: READ(intu,fmt[,err][,iostat][,end])[iolist] Reads from a specified character variable. Translates the data from character to binary format as specified by "fmt".
|