| IFLAG | general return codes |
| 0 | normal return |
| 25 | wrong input data structure |
| IFLAG | PLTMG and TRIGEN errors |
| 1 | zero pivot in sparse factorization |
| 2 | Newton method line search failed |
| 6 | illegal problem type |
| 7 | continuation procedure failed |
| 10 | multigraph iteration failed to converge |
| 11 | Newton (Newton/DD) iteration failed to converge |
| 24 | Error on one or more MPI processes |
| 48 | MPI was off for a command needing MPI |
| 49 | NPROC > NTF in load balance |
| 71 | no interface unknowns in DD solver |
| 72 | IPATH array not created |
| IFLAG | storage errors |
| 82 | storage exhausted in array IPATH |
| 83 | storage exhausted in arrays ITNODE and ITDOF |
| 84 | storage exhausted in arrays VX and VY |
| 85 | storage exhausted in array GF |
| 86 | storage exhausted in arrays IBNDRY and SF |
| IFLAG | data errors for triangulation |
| −31 | illegal ITNODE(K,*) K=1,2,3 |
| −32 | overlapping triangles in ITNODE |
| IFLAG | data errors for triangulation and skeleton |
| −40 | illegal value for NVF, NTF, or NBF |
| −41 | illegal IBNDRY(K,*) K=1,2 |
| −42 | illegal IBNDRY(3,*) |
| −43 | illegal IBNDRY(4,*) |
| −44 | incorrect circle center coordinates |
| −45 | arc greater than π/2 in length |
| −46 | error in linked edges |
| −47 | boundary vertex without two boundary edges |
| −48 | ITNODE and IBNDRY are not consistent |
| IFLAG | data errors for skeleton |
| −51 | illegal ITNODE(1,*) |
| −52 | illegal ITNODE(2,*) |
| −53 | skeleton tracing error |
| −54 | region specified in clockwise order |
| −55 | illegal ITNODE(3,*) |